Email is now an oligopoly, a service gatekept by a few big companies which does not follow the principles of net neutrality.

What are we left with?

You cannot set up a home email server.

You cannot set it up on a VPS.

You cannot set it up on your own datacenter.

At some point your IP range is bound to be banned... It's not if, it's when. Say goodbye to your email. Game over. No recourse.

The era of distributed, independent email servers is over.

What is more important to discuss, I think, is the fact that as of today, you only have two viable choices for browser engines