Why, I think, Nintendo has not lost its touch
I'm not going to argue against the belief held by most that Nintendo's gamecube library is weak compared to past systems. I don't think the decline in quality is that major, however. There has been several gamecube games I would dare call classics, even. But to say that anything Nintendo has done on gamecube is as brilliant or innovative as Mario 64 or Star Fox would be an outright lie.
However, Nintendo's software output for their portable hardware has improved drastically in recent years. If you look at what Nintendo developed for the Game Boy over the course of its life, you probably won't find more than a few classic games.
Now, look at what Nintendo has done in the short amount of time the GBA has been around. Many say the GBA has a better library than the current 3 consoles, and I totally agree with that. Wario Ware, Mario & Luigi, Advance Wars, Fire Emblem, Mario Kart Advance, etc are all regarded as excellent games. There are so many good Nintendo GBA games that many are either largely ignored or didn't make the cut in getting published in North America. Games like Kuru Kuru Kururin, Magical Vacation, Legend of Starfi, and the hugely underated Wario Land 4.
I think Nintendo's GBA output is so stellar compared to Nintendo's past portable software that it cancels out their dissapointing console software. And if you have a gameboy player, its like the SNES has been revived, and I don't mind reliving those glorious 16-bit days at all.