Nintendo Plans ‘Smooth Transition’ from Switch to Next Console by Using Players’ Nintendo Accounts

Generally, I think Nintendo is good about BC. Switch is kind of an exception because it doesn’t take discs. If they stick with the cartridge format (and they might), I’m sure it will be.

That said, if they go back to CDs, I’m fairly certain it won’t be. I think only the DS made a concerted effort to add an additional cartridge port for BC purposes. I don’t see them doing that again.