I have not used Microsoft or Google as a primary email provider in years, only Tuta or Proton. Never had a single issue communicating to either google or Microsoft.

People don’t use xmpp because it sucks, the UX is close to terrible and setting up a server is a hassle. The documentation is very lacking and the client options are very scarce. It is plain old and people have moved on to Matrix anyways. But still, I have used XMPP recently a lot thanks to JMP.chat. xmpp is very much not dead and there are very much improvements made regularly. What I’m trying to say is nobody uses xmpp anymore because it’s old and outdated, not because it was killed, because it was not.

Most websites are not bloated because they want to extinguish http wtf. They are huge because of stupid JS libraries and frameworks that web devs use for every little feature. I can guarantee you if Google or Facebook could make their website as pretty as they are while being 1kb, they fucking would, the bandwidth costs savings are worth it for them at their scale