While it is a new system with a new OS and interface, from a hardware perspective, the Wii can be justified as a revision of the Gamecube. That is why people were saying it. The prototype Wii was literally a GameCube and a Wii remote.
This is why I said, if anyone wishes to consider the Wii as a revision of the Gamecube, that would be IMO objectively the best revision of Nintendo hardware in company history. Otherwise, GBA SP. My personal favourite is the DS Lite, as I skipped the SP and actually played most of my GBA games on DS and DS Lite.
To consider Wii a revision is simply incorrect given the different branding, disc media, controller, OS, etc.
But I don't have the energy for much debating these days so I'm just gonna leave it at that.
Bet with Liquidlaser: I say PS5 and Xbox Series will sell more than 56 million combined by the end of 2023.