Agreed, I often see people say 3rd party support was bad on GameCube, I don't understand why.
They say that because PS2 had a mountain of 3rd party exclusives, and Xbox had a large 3rd party exclusive library as well. What those people don't get is that Nintendo's crappy mini-disks were preventing the lion's share of those 3rd party PS2 exclusives from being on it. Had Nintendo had disks that could have held the entire games without disk swapping those games would have come to GC. And those 3rd party Xbox exclusives were made for PC and easily ported to Xbox, because Xbox was basically a computer like most modern consoles.