That's an oddly cherry-picked version of a pattern. There was no compatibility between the NES, SNES, N64, or GameCube. Wii and Wii U each supported their predecessor's games, but the Switch did not. Those 2 out of 7 were outliers
The GBA (original and SP) also supported OG Gameboy games, but the Gameboy Micro only supported GBA games
The 3DS also had games from other consoles for sale in the eShop, but they were emulated (GB, GBC, Game Gear, NES, SNES). If you bought a 3DS before the price drop, you could also play some GBA games. These are also running natively, not emulation https://en-americas-support.nintendo.com/app/answers/detail/...
Game Boy Micro can still enter GBC mode, it just can't read any cartridges. It's missing the switch which is normally triggered by the cartridge shape, and also missing the voltage conversion circuitry.
The important part is that backwards compatibility became a focus after the Gamecube and it has been ever since. Like, this is just a fact. The Wii supported Gamecube games and controllers. Even the WiiU had the internal capability to run GC games, it just lacked the disc drive for it, and it ran Wii games just fine. The same goes for every single of their portable consoles (GB games work on the GBC, GB and GBC games work on the GBA, GBA games work on the Nintendo DS, etc).
