You're right, of course, but this simply switches the "reason not to use Fastmail" from "based in Australia" to "not e2e encrypted and can rat out your entire email history".
I don't see e2ee email happening anytime soon. The technology is just not very user friendly. And honestly, without e2ee, I don't put much trust into providers like Protonmail either because at some point the email is coming in as plain text and that's where one could always siphon it off.