Also, for email, if I use or recommend usage of any provider, as long as it supports IMAP (i.e. mostly all), it is almost trivial to do (or help others do) a mi

Also, for email, if I use or recommend usage of any provider, as long as it supports IMAP (i.e. mostly all), it is almost trivial to do (or help others do) a migration of emails to a new provider, if the need arises. Not so with federated services. I see there are some efforts, some solutions, but in general it looks like an afterthought.