I don't know about PS2, had one but that was by far my least played console of the three, but for sure I think the GC was a pretty weak gen for Nintendo first party games, at least compared to most of their other systems.

Sunshine was good not great and definitely the weakest 3D Mario by a long shot still today.
Wind Waker is very cool but at the time got branded as "kiddie" for being cel shaded and due to disappointment that it wasn't a more mature art style, and was only more widely appreciated later on in retrospect.

Smash of course was incredible as was Metroid Prime.
Double Dash was fantastic but at the time I think got downplayed as worse than MK64 purely for nostalgia, I initially felt the same but got over that feeling eventually and MK:DD is one of my most played games ever and easily my most played MK game.

Yeah Star Fox was a disappointment, but Fzero was incredible even though it wasn't the perfect sequel to FzX.

GC had a bunch of new games as the OP mentioned, but none of them were big yet.

GC was a bit weak on first party support, but also some weren't appreciated as much at the time as those games would eventually become with hindsight. I think the big issue is that Mario and Zelda failed to land to critical acclaim and as Nintendo's two most iconic and central single player franchises that kinda made the whole gen feel a bit lacking because for the first time Mario and Zelda weren't some of the top must-have games of a console generation, while N64 had three legendary Mario and Zelda games with M64 and OoT basically defining how 3D games should play still fresh in the minds of gamers.

Thats  nothing compared to what sony pushed out. Quality ofc is a opinion but again.

Dark cloud 1 and 2

Rogue galaxy

4 x socom

5x ratchet and clank

4x jak and daxter

3x sly recoon

Killzone

Jade cocoon

4x GT

And list goes on and on and on.

Quality maybe of opinion but general reception is a good indicator, for example Prime 1 and 2 will be picked by the majority of people over Killzone and Socom and so on. These were also games off the top of my head the were many more like the Donkey Kongas, DK Jungle Beat, Mario Parties, Mario Sports titles, Four Swords, Colloseum games, Wave Race, Battalion wars, Baten kaitos, Geist etc... It's even in quantity with the defining factor being quality which GC comes out on top comfortably imo Also Jade Cocoon is not a first party title its just published by Sony and Jade Cocoon 2 was the one on PS2 and was published by Ubisoft other wise you

I would think that the best lineup belongs to the company that can still sell these old games at full price almost 25 years later.

Wind waker, Sunshine (the BEST 3D Mario for me), Paper Mario: The Thousand year door, Metroid Prime, Chibi Robo, these are all games people still want to play and would pay money for.

Sony's lineup on the other hand did not stand the test of time as well. I'm sure the Ratchet, Sly and GT games were good, great even, but I don't believe there is a significant amount of people that want to play them nowadays.

Nintendo's games on the other hand are still sought after, sold and bought today, and at full price.

Doesnt matter. The topic asks 

https://gamrconnect.vgchartz.com/images/forums/icons/forum-page-header.png') no-repeat #ffffff;">Would you say the PS2 had better first party support than the GameCube?

And its clearly be a mile that its not.

Quality of the product or how well it is recieved doesnt matter when the question isnt that.

Sony made a lot and i mean A LOT mote games on ps2 then nintendo on the gamecube.

Quantity is your definition of better support sure but it's not a sole defining factor for everyone, you can make a lot more games than someone else but if that other person has a significantly higher amount of quality in their output and they're still outputting a good amount of titles regardless that for many people can count for more, case point in how far more GC first party games still stand out today than their PS2 counterparts.

Thats also a opinion. Socom is still being played online, god of war are highlt praised games still playable and soo are a lot of ps2 games.

Nintendo just cares about some of there legacy games a bit more then sony does thats verry true.

Doesnt make the sony games bad or unplayable in any way.

When talking about better first party support ofc we talk about the amount of games, or else we can just agree sony's output on ps5 is better then on ps2 becauze their games sell "more" 

Its not thou.

Who said about them being unplayable? GC first party stand out more long after that gen and that's just a fact Socom is still being played sure but it pales in comparison to Smash Bros. Melee still being a large active eSport 20 plus years later rivalling new releases like SF6, Socom isn't doing that against the likes of COD and BF and mind you Melee wasn't supported by Nintendo it was mainly off the back of grassroots communities which is outside of Nintendo preserving legacy.

Games like GOW and SOTC are praised and stand the test of time yes but that still doesn't make up the difference with their GC counterparts, it's not even about companies caring about legacy as with the example I made earlier put a load of people in a room today and guess whether they pick Killzone or Metroid Prime, whether they pick Echoes or Socom, whether they pick Dark Cloud or Wind Waker, whether they pick Rogue Galaxy or Paper Mario TTYD etc... More often than not it'll be the GC first party picked. Nothing wrong with the other games the GC offering is just generally seen as better quality by most which is understandable as they're created to sell the platform while it can be argued PS2 offering were created more so to compliment the library.

It's probably the closest the 2 have gotten in terms of 1st party offerings. PS2 had such a diverse line up even on that front. From Siren to GT. Still hoping for a Dark Cloud 3.

But other than SotC, I don't think that it reached the highs of MP1+2, Melee and TTYD.

Provably a toss up depending on if the emphasis is placed I'm variety or peaks tbh.