Man, the Gamecube must have really sucked if it was a miserable failure despite having such great games.
amazing hardware, great games...
2 issues that held it back were, #1 the controller, and #2 the mini DVD sized discs.
the controller had 4 buttons less than the controllers of the other 2 consoles, that meant ports often played really weirdly.
and it had sticks with an octagonal gate and the stick mechanisms themselves also had what basically felt like groves the stick slid into that went 8 ways. this made stick movements feel weird in some genres.
the 4 buttons it had less did in many games necessitate button combinations that were a single button press on the other 2 consoles. so controls felt more convoluted and way less intuitive.
in GoldenEye Rogue Agent for example you could dual wield guns, which was the main gameplay feature of the game.
on Xbox you just press X or A to pick up/drop/switch the left and right weapons respectively...
on GameCube you had to hold down A, and then press L or R to do this.
the sticks had no click buttons, it had only 3 shoulder buttons and no Select button. missing stick clicks also often resulted in weird button mappings.
and then the Discs were just too small to fit all the data on. so multiplat games often had compressed textures that looked noticeably grainy.
Ubisoft was especially guilty of this, where you could count the pixels on some textures on GC.