Email as a protocol needs to die. The stuff we do by email can be done PROPERLY AND BETTER by just basing the same top layers on something else that actually works and does the end-to-end encryption, domain verification, signing, authnetication etc. for you anway).
That something else does not exist and will never exist, because the big Internet companies won't let it exist. SMTP email exists and can be used outside the control of the big companies.
Protocols like Jabber would suffer from the same issues that you claim email has if it were adopted as a replacement for SMTP. .
What you are really proposing is, in effect, that instead of email, people should just use the plethora of proprietary messaging services.