An analogy:

Stalin took over USSR in 20s by pressuring specific councils (“soviets”), because a council could vote to recall its representative to a council of next level any time, and that would cause a chain reaction for that council and so on. So every representative of the upper level could be removed by pressuring\persuading only the initial council they were delegated from, and one wouldn’t have to wait for any election or such. Eventually one could get a jackpot combination by removing unpleasant representatives through pressure.

So with email, changing mail servers is not such a good solution, because one could still pressure a registry to unregister the domain name, a hoster to stop hosting it, an ISP to do something else …

Maybe cryptographic identities should be used for users and addresses and even name registries (using hex strings as addresses is inconvenient, I can’t even remember phone numbers), while storage and service should be separated from that. Like in NOSTR.