Yes, if all the MTA admins refused to SMTP with Google, Microsoft and Yahoo right from the start email would still work. Right now it doesn't. We don't want a repeat of that, so let's defederate from any big corp or anyone who federates with any such.
If you don't, you're dead in the long run.
You can block Meta at the AS level for your instance firewall, and also at federation level so that you can defederate from second order offenders.