Bill Gates already had this idea. All efforts to change email were already documented 25 years ago. The biggest changes are it is more centralized these days, SPF/DKIM/DMARC, JMAP innovation, oh... and one more thing! It is HUGE!! HTML email is the default...

Yeah I remember this from "The Road Ahead" which I chanced upon one time in the 90s. I thought it was a silly idea.