The Problem you describe applies to reddit also, however the solution on lemmy is in your question.
If a community gets scuttled on reddit, where are you going to go? How do you make the transition smooth enough that you’ll retain most of the community. You’re pretty up shit creek in this scenario.
On lemmy if the main community is scuttled, there are already 5 new communities set up, with the same UX/app/login creds. The members can transition easily and carry on being wonderfully niche.
Yes technically the owners of the instance “have all the control”, but it’s in the same way that a friend lending you their car “has all the control”. If they’re a dick or need it back you can just ask someone else. As opposed to reddit which is more like welfare, if the government decides to kick you off, you’re shit out of luck