Matrix is great and has bridge support for all 4 chat services mentioned.

Most people will not host their own. They'd still be in someone else's garden.

Just don't sign up to any of the biggest three once the protocol reaches mass adoption, and that's not a problem because you can always leave without losing the ability to communicate if someone does something shady, and your private data is private.

Additionally having a long tail with 30-70% of the users makes it impossible to buy. And you probably don't even have to go that far, just not using element is probably enough to prevent matrix from trying it even if they wanted to (which it's clear they don't because they make it easy to leave).

We don't have to 'leave email' or 'leave tcp/ip' every few years because the TOS requires handing over your firstborn or because http is running experiments to see how many people will commit suicide. The idea is borderline-incoherent.

SMS?

That really doesn’t work when phone carriers give everyone free WhatsApp traffic. Which is why it’s so popular in my country, other than inertia.

There's free as in beer, free as in speech, and free as in "candy" scrawled on the side of a panel van.

If you use something because someone is paying to shove it down your throat, you will pay a thousand fold once they win their monopoly.