It's an unfortunate reality but that's probably going to have to happen. Instances can't be expected to grow and maintain on pure goodwill. Some might get by with donations but it's pretty known that Mastodon servers that couldn't support themselves on donations vanished. It's a huge ask for someone to pay money, time and effort to run a server for perpetuity. Usually you can only ask for 2 out of the 3 lol.

We already saw the original lemmynsfw get overwhelmed and just want to shut it down and hand it to someone else because they were having to put in so much work.

Hopefully because Lemmy is opt in in every sense, instance owners can do an ad setup that isn't intrusive or over bearing.

Otherwise it's just the big instances that are donation covered that stay and grow and Lemmy just becomes centralized around 5 servers or something.