Why was the GBA Successful but the Gamecube wasn't

[Salnax]

1. The GBA launched at half the GameCube's price and its games were often significantly cheaper.
2. There was no major competition in the handheld space from 2001 to 2004.
3. The GBA had main series Pokemon games, which can basically carry any platform to decent success.
4. The GBA was compatible with something like 2000 GB and GBC games dating back to the 80's. The GameCube couldn't even play N64 games.
5. The GBA was a great candidate for porting/remaking NES and SNES games, which were high quality games that weren't easily available. Examples include the Super Mario Advance quadrilogy, Link to the Past, Kirby: Nightmare in Dream Land, Classic NES series, and various compilations.
6. When Nintendo released the DS, they continued to support the GBA for a couple more years with the Game Boy Micro, the Player's Choice line, Pokemon Mystery Dungeon, Mario spinoffs, publishing Square Enix ports, etc. Something like 20 to 25% of GBA's sold in Japan were sold after the DS's launch.