If that were true, mail providers would already offer this. In fact, I suspect some unsophisticated ones probably do, with all unrecognised senders having their emails sent to the recipient's Spam folder, with a few exceptions for DKIM-signed mail from frequently seen addresses, like Amazon receipts.
Appeal to Authority?
If people truly had any interest in an email replacement, mail providers would already offer this. So why are you asking your original question?
https://www.thoughtco.com/logical-fallacies-appeal-to-author...
No, appeal to the market. If there is demand for a product in an interoperable market, then one would expect an entrepreneur to create that product. (Admittedly, the unusual economics of email services mean that market forces might differ from theoretical models, but there could still be some pressure for competing providers to add features that users want).
> If people truly had any interest in an email replacement, mail providers would already offer this.
There are dozens of replacements for (some aspects of) email, including WhatsApp and Twitter. To be fair, these services do (I think) have mechanisms that effectively limit your interaction to just people you already know, but the fact that email still exists (and doesn't have this restriction) suggests that there is value in the openness that it offers.
A totally private (white list only, friends and family) email address would be very attractive to a lot of people.
Lots of people would want 2 email addresses with varying levels of restriction --- one public and one private. I do this now but my private address is lacking any strict control to keep it this way.