Just for the record, I don't think hardware power was a problem for the Gamecube (some people point out that the Cube didn't succeed despite being quite capable). I think the problem was that the one year old PS2 was already running at full steam and capable of doing 90% of the 'Cube's capabilities. There simply wasn't a NEED for the Gamecube outside of Nintendo's titles much like how the PS3/360 were already in the Wii U's league as far as the general public was concerned.

3 consoles with similar specs? No.

In that case, it's honestly Microsoft that's the odd man out. 

Nintendo would have a 10 million unit headstart if they managed their headstart more wisely and had a console clearly better than the existing 360/PS3. MS wouldn't be able to catch them, especially not at $500 and 12 months later. 

Sony might win again, but even they probably would need until 2015 to overtake. 

Nintendo will always be unique because of their games ... the SNES/Genesis/Turbo Grafx 16 were similar technically, but do you mistake the SNES for the other two? I don't think so. 

Do you think that after the N64, GC and Wii, consoles that had some kind of negative perception from gamers or media, that people would be willing to jump on the Nintendo bandwagon before seeing what Sony and MIcrosoft have to offer. Not to mention that things like online infrastructure and features - which people many people complain about NIntendo platforms for -  would improve more gradually rather than immediately.

Indeed, all that and free online would have been an instant win

Whats key in his response is that he said all the big 3rd party games. The gamecube didnt have Final Fantasy X, MSG2, Tekken and GTA. The Massive 3rd party games in the early critical launch year period. Also the Gamecube came a year after the ps2 and lacked a key feature (DVD). Too many elements to consider to say the high end approach didn't work for them. Also, so much was wrong with N64 that its lucky to have managed 30m+.

Many things have changed that would have made a high end wii U likely to succeed. Developers do not hand out exclusives for free like they once did, all those same games that were exlcusive to the Playstation were made multiplatform for the compatible platforms in the following gen(PS3/360). If the Wii U was a system designed with core audience in mind and aligned to devs next gen vision, I bet we would be seeing Witcher 3, FFXV and other 3rd party next gen exclusives arriving on the system aswell. 

For me personally, If I thought the Wii U was going to recieve the same 3rd party games as the PS4 and XB1 and perform comparably, I would have bought one near launch and wouldn't get a PS4 till late in the generation. However Nintendo would have had to do more then just up its horse power. Dev support would have always been weak during its 1st year because the system arrived early and 3rd parties were finishing up/mid way through the last era of ps3/360 games.  As such Nintendo was always going to need their A game in the first 6-9months but they simply didn't have the teams to provide titles in Q1 and Q2. 

Alternatively they could have launched the Wii U alongside the PS4 and Xbone with Pikmin3, Mario World 3D and WindWaker HD as launch titles alongside Ubi's and EA's offerings. They probably would be outselling Xbox One right now.

The GameCube really in hindsight was a bizarre console.

Even overlooking the strange design ... it's like Nintendo intentionally said "hey Nintendo fans! Do you like Mario 64? How about a Mario game that's nothing like that at all! Bet you loved Zelda: Ocarina of Time, right? We've totally changed it and gone in a Powerpuff Girls artsyle! GoldenEye was awesome right? Especially multiplayer! Well here's Metroid Prime, a slow paced FPA with no multiplayer! Did you like Star Fox 64? How about we turn that into a Zelda type game? Mario Kart 64 was good but we need to change that formula too. Like Rare? Great. Perfect Dark and Banjo-Kazooie will be awesome ... too bad we sold them! Donkey Kong Country or 64? How about a Donkey Kong platformer with bongos instead?"

Smash Brothers was like literally the only straight forward sequel Nintendo made for the GameCube, and not surprisingly it was the only one pretty much universally well received.

It's like with every other thing they did well on the N64, they went out of their way to completely change what people liked about those franchises or needlessly meddle with the formula.

The also SAT on the GameCube chipset for an entire year, opting to continue supporting the N64 with a lot of late-gen projects like Perfect Dark that barely ran on the N64. The GameCube hardware and design was completely finished by August 2000, but they weren't ready with games until September 2001. 

Nintendo will always be unique because of their games... . Kinda proves my point.

Yes, but not just with hardware alone. The 3rd party support. It's always instrumental in the success.

Sony's consoles never lost that support in all the previous generations. N64 and GC struggled due to lack of games. They were not just some random manifestations without reason.

N64 was impeded by cartridge ROMs which kept the devs away and closer to PS1 hardware whereas the GC struggled even more missing most of the important first person shooters. GC had good specs but was skewed by most devs as for children and less adults or teens.

When GTA San Andreas struck PS2, GC's fate was sealed. In both Ninty lacklustre generations, it was always their 1st party working out at stake.

No. They tried that, it was called the GameCube. It didn't work then and it certainly won't now.