Don't forget about when IM networks actually used open standards instead of closed proprietary protocols. Managing all of my accounts through pidgin was a breeze, and didn't leave me swapping between half a dozen different programs trying to remember which networks somebody would typically use.

> E2ee helps mostly against server owner, and you eliminate this risk by being your own server owner.

Unfortunately you only eliminate it by being your own server owner _and_ your recipient being their own server owner. Take a look at email: I might not want to use e2ee because I self-host, but the second I send an email to a friend hosted on gmail, Google gets all the content.

I think federation does have its place (for different reasons) but it unfortunately isn't enough for privacy.

> Just do it on your own server

What if I don't have and don't want my own server?

You run your own datacenter?

Your Signal client has all the messages stored unencrypted (this is true because you can read them all, and search all the local messages).

What's preventing the client from dumping all the messages to a single file, encrypt it with a public key of the other running instance of Signal logged in to the same account, and send it, so that your other device can decrypt the file and import all the messages?

First people want full security, but when they encounter inconveniences that come with true full security, they start wanting convenience. What works best is a very very very good promise of security without e2ee, as shown by Telegram. It's users just know that Telegram is the most protected messages, and they are happy with it's advanced features.