Google did a security research around ssl and a crazy percentage of people think the lock icon is actually a handbag icon. The rest of the research highlighted how most users aren’t able to make informed choices, most people lack the technical basis to make those choices.

So what's the overlap of "people who care enough about e2ee for it to matter whether a message they're sending is encrypted or not" and "people who think the lock icon next to the send button in the encrypted messenging app they downloaded is a handbag"

I'm willing to wager it's not as big as you're trying to imply.