The big point you're missing here is that he was tried and convicted. In fact, he pled guilty. The issue was already pushed through the criminal justice system in California.

He fled just before his sentencing, after serving 42 days in prison while waiting for the trial and sentencing (which some are saying was enough jail time).

There have been fewer than 10 attempts to arrest him in 32 years.

Did he rape other girls in that time? who knows?

I'm sure that the mother has suffered plenty, and would change her decision that day in a heartbeat. I'm not sure if Polanski has suffered, or even expressed remorse about what he's done.