I used to have a Canon Pixma, and the SANE drivers recognized it and scanned from it with no issues, down to the ADF feeder. It was really surprisingly simple, zero setup configuration.
I basically just used the preinstalled software, Skanlite, and it showed with the scanner pre-selected and ready to go.
Of course, YMMV.
I think it’s the “basically” part in basically right back where we started that makes the difference. Even if 100% of Fediverse users were on a single instance, once that instance starts pulling Musk moves, the users can move somewhere else.
Only if that instance defederates from everyone else do we get the Twitter situation again. Or, since that’s actually what happened, Truth Social, which I think is just a slightly modified Mastodon instance with federation disabled/deactivated.