> I don't love flock but IMO the only realistic way to get rid of license plates would be mandatory speed governors that keep vehicles from going more than like 15mph.

I don't understand this reasoning. License plates don't stop speeding from happening. Removing license plates wouldn't prevent enforcement of speed limits either. A cop can pull over and ticket someone without a license plate just as easily as they do now.

At best they're good for a small number of situations where they help identify a car used in a crime (say a hit and run) but even then plenty of crimes are committed using cars that can't be linked back to the driver (stolen for example) or where the plates have been removed/obscured.