All true. But Wii does play Gamecube disks, had a lot of the same internal architecture, and was called "two GameCube taped together" quite frequently; Switch does not play Wii U games, GBA does not play SNES cartridges.
None of them are revisions, obviously. They're all clearly new systems that just happen to share some games and technology with prior systems.
Bet with Liquidlaser: I say PS5 and Xbox Series X will sell more than 56 million combined by the end of 2023.