The GameCube used minidvds that had only 30% of the storage space of standard dvds.
The result was a generational game like FF7 was only possible on the PlayStation.
The only reason I have a switch is Nintendo ip otherwise everything else beats it hands down.
With aging Nintendo hardware now all of it can be emulated in a pc. I barely use it anymore.
I'd have to think about it, but I might defend the NES, SNES, and Gamecube as the best consoles of their generations, if we're just looking at the consoles themselves. The first two do even better if we consider the games, too (though the GC is plainly not its generation's frontrunner, if you add that—the lack of 3rd party interest really hurt it, its library is tiny, and consists mostly of few great Nintendo games and a bunch of terrible shovelware).
I'd put the N64 at a tie with the Playstation. The N64 looked better and had four-player support out of the box, which made a big difference in how many games supported four players. The analog stick on the controllers was a real problem, though, as was the storage size. Then again, the Playstation launched without any analog sticks. Call it a draw.
It's only really with the Wii that they stopped credibly trying to keep up (and IMO the Wii's various gimmicks don't make up for its deficiencies, among which I count some of those same gimmicks)
GameCube's proprietary "micro-DVDs" also meant limited game sizes compared to PS2. And PS2 could play DVDs, which was a strategic advantage at the time. With both Sony and Microsoft now competing for hardware dominance, however, it became a tougher position for Nintendo to hold, plus the company was not willing to sell consoles at a loss (as I believe both Sony and Microsoft did at first, to gain adoption).
So both N64 and GameCube were limited in significant ways, and it cost Nintendo its market dominance. The Wii was an example of Nintendo taking the console tech in a totally different direction than its peers, explicitly focusing on motion controllers and casual gamers. It was a smash hit, but eventually the novelty of the Wii wore off. The Wii U was a flop. The Switch successfully blended their portable and console offerings.
PS2 was barely more expensive than a decent DVD player, at the time, and came out before most folks had a DVD player. And it played DVDs. Gamecube didn't. This made the Gamecube a second console for most people... which meant they didn't get it at all, if they only had one console. PS2 also played PS1 games, which meant some gamers had a large library that could be played on it on day 1. GC didn't play N64 games.
Nothing else is really needed to explain the GC's weak sales relative to the PS2.