Gamecube was off tone for Nintendo, that’s for sure.
I think Nintendo tried to hard to make Gamecube into a PlayStation, perhaps with a Sega attitude. It’s probably the only generation where Nintendo felt like a trend follower rather than a trendsetter. They afterward went back to their older philosophy (slightly changed, and branded “blue ocean”) and didn’t repeat that mistake again.
This is kind of related to the other post, but Nintendo does Nintendo extremely well. They shouldn’t try to do Sega or Sony, especially when they can sell 100m-160m hardware and 900m+ software just being Nintendo. No one is likely to do Sony better than Sony—ask Microsoft… but only after an injection of non-PR/truth serum.