Piefed might work a bit different but on Lemmy there is one key aspect where instance matters, and that's community discoverability. Discoverability works only on local communities and for communities that my instance is already aware. The way to make the instance aware of a community is by knowing about it beforehand and doing a direct search. So for example if we take a completely unknown community like [email protected] and I just searched "mediashare" on lemm.ee I wouldn't find it. For anyone testing on lemm.ee that's now discoverable because I also searched "[email protected]" which is a direct link and made it discoverable for everyone else. In that sense lemmy.world probably has the best overview of all communities because more people equals more people checking out different communities which makes the instance aware of more communities which makes the search for communities more functional.
IMO this is a downside of Lemmy and should be fixed. All instances should have a list of all the communities other federated instances have. It would significantly improve the search functionality.
Obviously. You could be the next Phil Harrison. Failed with Atari, got picked up by MS to lead Xbox. Failed with Xbox One, got picked up by Google to lead Stadia. Failed with Stadia and is currently keeping a low profile because he probably understood that failing any higher than Google is going to be a long shot.