Registries have always had the ability to revoke number assignments; RPKI just makes this revocation slightly more forceful. You're going to have a bad time announcing prefixes that don't belong to you, even in the absence of RPKI.

We're all internetworking at the pleasure of IANA. Getting them out of the picture, and removing their ability to deplatform Internet participants, is a much larger task than just moving away from RPKI. We'd need to completely rethink how ASN and IP assignments are done.