The Gamecube didn't offer developers or consumers much except for fast hardware, which by itself is useless. Unlike the N64, the Gamecube wasn't riding on the coat-tails of an extremely successful console. The Gamecube needed to create new opportunities and attract new developers and consumers that Nintendo didn't already have but instead it just tried to tear down some of the development/hardware obstacles that the N64 struggled with and repackage the same console concept. Maybe Nintendo over-estimated the impact that the N64's poor hardware decisions had on the console's success and thought that if they made a developer-friendly successor that used disc-based media that everybody who left Nintendo for Sony would just come back on launch day. The truth is that even if the N64 had been a CD-based console it is likely that Sony would have still taken over the market in the late 90's because Sony was better at listening to 3rd party developers and creating the platform that they wanted.

The reality is that the Gamecube is a console that was designed to compete with the Playstation on Sony's turf, but the problem is that Sony does this job way better than Nintendo ever could and so Nintendo got spanked. That is not to say that Nintendo cannot still go head-to-head with and sometimes beat Sony in the console wars, but Nintendo figured out after that Gamecube that the only way they can do this is by innovating and carving out new markets for itself. Sony plays the long-term game by putting out low-risk hardware and focusing on relationships with developers, timed-exclusives and excellent marketing. The Gamecube was made because Nintendo was used to having control over Sony's market in the SNES days when its only competition was Sega. The N64's hardware limitations masked the underlying shift that occurred in the late 90's when Sony took over Nintendo's old turf and Nintendo was under the mistaken impression that it could get back to the SNES glory days just by doing the same old thing.

I still yet to know what happened to GCN, just as far as i knew it's because of 3D GTA games and Gran Turismo were extremely popular on the PS2 according to top selling.

And then there's little interesting story which i think something probably drove them uninterested in GCN... I've heard many old Nintendo fans back in 2000s were disappointed with GCN first party games because of concepts or presentations, which i'm complete speechless, like there're thousands of reasons i disagree with them, or.... maybe commercially/marketing were complete failures.

I just wanted to call out these posts, because I agree with each of them.

I'll add that in the gaming community there is a massive hipster faction (I know this group because I'm a bit of a retro-gaming hipster myself) that likes things that were failures because they were failures. There is a lot of ignoring of reality and instead focusing on a mythological version of gaming history that didn't really happen. Gamecube, for lack of a better phrase: didn't feel important or special.

A slew of reasons, but perhaps the biggest is just the increase of competition and particularly the monster that was the PS2 - it basically destroyed Sega and the Dreamcast, and marginalized MS and Nintendo. 

You also had the lack of appealing, mass-market software. Even the great games largely tended to be niche, like the cell-shaded Zelda and the weird Mario game. 

The funky console and controller design wasn't particularly appealing. Also had sort of a "cute" look that somewhat pigeonholed it as a "kiddie" console (despite having plenty of "mature" titles like the RE games and Eternal Darkness.

Lack of third party support. Although the console was actually comparable in terms of power, Nintendo negated some of this with its exclusive disk media which was quite a bit smaller than the competition in terms of space.

Not terribly well marketed 

It was mostly about the games. Nintendo experimented too much with their flagship franchises, and mostly delivered games fans weren’t waiting for, and were even “objectively” worse than their N64 predecessors. Beside the games it already started with a bad image; the purple GameCube was the main GameCube marketed (like how Wii “is” white, and Switch “is” neon blue/pink) and that made it look like a toy, or even a ‘lunchbox’ to the exceptionally pessimistic, in the eyes of the hardcore audience. A negative initial impression by the hardcore carries over to the perception of the wider audience. And so even though the GameCube was technically superior to PS2 in every way beside storage, the former was seen as an inferior console for kids while the latter remained the go-to gaming system for the masses.

I'd dispute this.

Nintendo's profits were unusually low during the Gamecube considering the booming handheld business. Most of Nintendo's operational, marketing, and R&D expenses were for the benefit of the home console division. Gamecube couldn't have been making enough profit to account for those expenses.

THE EVIDENCE

https://www.nintendo.co.jp/ir/pdf/2005/051124e.pdf

This shows Nintendo had 515 billion yen in revenue, 115 to Gamecube meaning around 80% of the total revenue is from the handheld division.

Nintendo also showed that expenses were 405 billion with manufacturing and sales costs amounted to 300 billion yen, and internal expenses (employee salaries, and such) costing the other 105 billion (this is before corporate acquisition/sales costs/profits, exchanges, and taxation).

In order for Gamecube to break even, it would need somewhere around 80-90% profit margins on manufacturing+shipment+marketing, which we know is certainly untrue.

Handhelds were 80% of Nintendo's revenue income, and almost certainly had higher profit margins on sales vs (manufacturing+shipment+marketing). They definitely did not cost anywhere near as much on the internal side as handheld teams are typically far smaller than home console teams and most of the internal focus was on home console, not handheld.

Spread sheeting it under the assumption that Gamecube hardware and software had the same profit margins as handhelds (which isn't true, handheld definitely had higher margins), the home console division still makes a loss. But it's not rocket science to make this deduction, the home console division (115B) generates barely more money than internal costs (105B), while the handheld division generates nearly 4 times as much. Unless handheld hardware cost more to manufacture and ship than home console hardware (an absurd consideration), Gamecube can't be profitable.

IN CONCLUSION

The reality: the belief of "But at least Gamecube was profitable!" is a myth.

The home console division was making a loss, and it cut into Nintendo's massive profits made by the handheld division.

How much time ya got? Let's see...

1. The PS2 had a one-year headstart. It didn't come flying out of the gate, but that's an entire year to establish a foothold and marketshare unchallenged.
   
   1. That DVD drive really was a gamechanger. Going from VHS to DVD was a tremendous jump in graphical fidelity and playback quality for most people, and the PS2 was one of the cheapest and easiest to acquire DVD players on the market. It really helped justify the PS2's place in living rooms until the deluge of games came, while the GCN had no such fallback.
2. How do you market a purple lunch pail next to big,black, badass behemoths like the PS2 and Xbox? Imagine telling your friends you bought the Fischer-Price toy over the PS2 that everyone else has.
   
   1. Yes, the mini-discs were a factor. Not in actual performance; like you said, most games from that gen could fit within the confines of the 1.5GB space, especially with GCN's compression technology (and if they couldn't, making multi-disc games weren't a big deal; those discs were super cheap). But like the above, they came across as very kiddy, and no one between the ages of 10 and 25 got time for dat. For the real space issues, see the point below on memory cards.
3.  The controller, again, looked like a toy meant for young kids. With all of it's bright colors and bean-shaped buttons, it looked like something you'd find on some cheap console in the Toys section at Wal-Mart that with a few built-in games that are either mind-numbingly simple, educational but boring, or some Chinese knockoff. The Dual Shock 2 was an evolution of an already-loved controller, and The Duke was the gaming equivalent of a large Chevy or BMW; compensating for something, but a bastion of raw manliness nonetheless.
   
   
4. Nintendo's first party memory cards were a freaking joke. Most people think that Nintendo's cheapness with storage started with Wii, but go look up how much memory came on GCN memory cards compared to PS2 memory cards (not to ignore the fact that Xbox had a built-in hard drive). Many games, namely sports titles like the Maddens, had save files that were too large for a single first party card, so devs had to find ways to cut corners or features. I personally had a MadCatz card that held 16x the space of the largest first party card; it was popular, but notorious for corruption and losing previous saves, but thankfully mine never ran into any problems for almost a decade.
5. The GCN first party output is easily one of the weirdest and least celebrated (at the time) generations in Nintendo's history, rivaled only by the Wii U. Wind Waker (more on that later), Mario Sunshine, both Star Foxes, DK Jungle Beat were all considered offbeat departures from what fans were expecting after their N64 entries. Waverace: BS, NBA Courtside, Pikmin, Animal Crossing were all too niche to really capture an audience on a system that struggled out of the gate.
   
   I already know that I will get a few replies on this one about how beloved and celebrated some of the games I mentioned are now, but the keyword is NOW. Were you there for Spaceworld 2001, for the reveal of Cel-da? On April Fool's Day, no less? Isn't Sunshine generally considered the worst 3D Mario game in the series? And boy, don't get me started on Star Fox... point is, people didn't think Nintendo was bringing their A-game at the time. Even Mario Kart: Double Dash's new and unique was often panned as gimmicky and adding little to the gameplay. We fondly look back on many of these games now, but they didn't light the world ablaze when they launched almost two decades ago.
6. Grand Theft Auto 3. There aren't enough words to express how much of a gamechanger this title was. GTA3 is THE hood ornament of that generation. It was the cultural zeitgeist of the early 2000s. Being the one console without it was the equivalent of being the one guy in the locker room who was still a virgin.

Heh, there are so many reasons to describe why it failed.  Here are a few.

1) PS2 had all of the really fun games.  There was no reason to get a Gamecube.  I did like the Fire Emblem on the Gamecube.  The other games were decent, but skippable.

2) It was like the N64 but worse.  N64 already lost to Playstation.  And yet even some Nintendo fans were pissed.  Like Sunshine and Wind Waker were worse than their N64 counterparts.  Personally, I didn't care for either system, but some N64 fans got alienated.

3) Games weren't 2D.  Up til this point, the only Nintendo systems I'd liked were the 2D ones: NES and SNES.  And of course I was far from alone on this.  Nintendo's 2D games were more popular and they didn't make them.

That more or less sums it up.

My phat launch PS2 is fine, but my Gamecube controllers...

Can't be bothered to look up/quote the post but those discs really were a problem. Games like Metal Gear Solid and Resident Evil 4 were multiple discs. When you had ports of games like SSX Tricky that were missing most of the video content or games like True Crime that was missing half the soundtrack or mission variety, that was a big deal. And again, even when the GameCube got ports, it was often several months to a year later than the other versions. AND as awesome as the GameCube controller was, it was missing buttons. No "L3" or "R3". No "select" button. Only three shoulder buttons. They crippled themselves.

Don't get me wrong, the 'Cube was still my favorite console of the generation. I tried to grab every multiplatform game on that system...but they were often so gimped, I had to go back to the store and swap them out for the PS2 version. Even though it was more powerful, the ports were often afterthoughts. You got Splinter Cell with "exclusive intro cutscene" that wasn't impressive but then the actual levels would be reworked and shrank down. Nintendo's stuff was still great to me. It just wasn't enough.

At the end of the gen, I owned around 50 GameCube titles and about 150 PS2 games. My heart was with Nintendo but my wallet said otherwise.