I think the reason most people don't flee Florida is the cost of relocation. They have jobs, houses, family, etc. that may be difficult, if not impossible, to relocate.
Moving from Reddit to Lemmy is free, but does require a bit of effort in learning the local-speak (instance, Fediverse, federation/defederation, etc.) and sorting through choosing an instance and creating an account, then wondering if you created your account on an instance that fits you best, then figuring out how to find groups of interest, and so on. It isn't like opening Twitter and poof, you have all of Twitter ready to read. It's a bit more complicated, requiring mental effort and a bit of time, so most people won't bother.