The whole point is in avoiding starting with an AOL like service. So far only big matrix provider are reliable and performant enough to be usable. This is @gmail.com all over again but with @matrix.org tld.

Except you won't be able to carry your messages from a tld to another when you decide to rely on another domain name (your own or someone else's).

How long before Matrix foundation send messages telling users they are going to delete their rooms and messages if they don't log in once a year ? Or that they are now restricted your account to matrix.org rooms to "save operating costs" ?

The whole tech stack is free but operating costs are not.