This all sounds like a great proposal to fix some major problems with email, but it doesn't address the biggest issue. The reason these issues haven't been fixe

This all sounds like a great proposal to fix some major problems with email, but it doesn't address the biggest issue. The reason these issues haven't been fixed is vendor lock-in. Making it "insanely difficult" to self-host is a feature, not a bug. Try migrating off of google or whatever your email provider is. You will find that you have 300 accounts that use email as your core identity provider. Getting locked out of your account is on par with having your house burned down. Email is a huge moat that these big companies are not going to let go of easily.