GameCube and Xbox were a lot more advanced than the PS2, but had far fewer problems..... I would bet the only reason the Wii has more problems than GameCube is it is being produced a bejesus lot faster than any console before.
I was suggesting more of a combination of issues more than one thing. There are always exceptions. For whatever the reason, failure rates are higher over the past 2 generations than in previous ones. I own a 2600, 5200, NES, SNES, GENISIS, N64, PS2, GCN, PS3 and Wii. None of the old ones failed on me, and I know about the problems with the PS2 last gen.
Sure it may be anecdotal evidence, but it is no less valid than the "I've got X friends with Wii....." posts that are currently populating this thread.