Here is something to downvote, a series of questions:
What if email were "pickup only" _from the sender_. Not from some intermediary recipient, e.g., an "email provider". What if the the recipient had to identify acceptable senders before they could "send" mail to the recipient. Arguably this already happens every time an email recpient gives out their email address to some email sender. What if the sender did not "send" mail but instead uploaded it to host run by the sender and accessible by the recipient. Then the recipient retrieves the mail from the sender.
In the past, one large email provider had an RSS feed for a user's inbox. What if the RSS feed is not provided by some third party "email provider" but by _senders_. What if the feed indicates whether there is new mail waiting to be retrieved by the recipient. Arguably, something like this already happens, albeit using third party intermediaries, for example as millions of people use non-public webpages on third party websites to communicate with each other, instead of using email. Recipients check these pages for comments or messages from "senders".
A simpler idea that requires no changes to any email protocol, which I have tested successfully on home network, is for sender and recipient to be on a peer-to-peer overlay and run their own SMTP servers, like the original internet. The sender SMTP server communicates directly with the receiver's SMTP server, not a third party SMTP server run by an "email provider". Obviously, sender and receiver should not invite anyone onto this network who they do not know and from which they do not want to receive email.
The fundamental problem with email is that personal, non-commercial email is mixed with commercial email, mail that is selling something. That's beneficial to marketers, but not email users. Any change to email that threatens to exclude the unsolicited, commercial email will be opposed fervently.