I’ve tried to right this “meeting should be an email” battle but the reality is shocking: nobody reads anything, for the most part, and when they do, they act like they didn’t.

Exactly. "This meeting could have been an E-mail" is only true if people read and respond to their E-mail. I usually will try E-mail first, but if I don't get a response or if the expected action is not taken--I sigh and break out the meeting invite.