So with the authorities and witnesses unable to take note of a license plate, the California traffic laws basically become unenforceable. Why is this allowed to happen?
it's California?
FYI: California Vehicle Code citations almost all require a peace officer to be the direct witness of the event. So even if you call in and send video of a car running a red light, speeding, driving aggressively, etc, that alone cannot be used to issue a citation. You have to hope for the cop to show up and see it himself.
(Note that a lot of crazy crap that people do in cars are likely against the California Penal Code too -- for example, cutting someone off or brake-checking them can potentially constitute assault if the intention is to physically threaten the safety of the other driver with your car... And a video works just fine for that.)