[SmallDeadGuy]

Nintendo have typically been pretty good with backwards compatibility as newer versions of consoles come out. GBAs could play GB/GBC games. DS could play GBA games. 3DS could play DS. Wii could play GC games. Wii U could play Wii games.

The Switch is an outlier in that regard but mostly because the hardware is so different from previous consoles. It could never support the 2 screens required for DS/3DS or some Wii U games, nor is it big enough to fit Wii U disks anyway. But it wouldn't surprise me if the Switch 2 could play Switch 1 games.

Nintendo also typically put entire games on their cartridges, and day 1 patches are for bug fixes only and are optional. If you keep the cartridges and your console, you keep your games perfectly fine. Or you can go out and buy cartridges second hand. And digital downloads will also still function, like my 3DS still has my digital purchases even if the eshop is gone. I just can't purchase new games anymore, for a 12 year old system.