Email lets anyone send any message to anyone else. All you need is an email address. Most of the world’s email is spam.
Email is largely text plus attached files. Any way to share files will work as a substitute for email. Would anyone ever consider having an open file upload where anyone could upload whatever they want?
We should move to an alternative approach where you agree to let someone upload messages to our server. Spam would be zero, because you couldn’t upload that crap without first getting access.
Email could still be around for messages from people you don’t know.