SOL in CA for rape is 10 years. There are allegations out there well within that time. Also, may vary by other states from which there are accusations.
While the earlier claims might not be criminally prosecutable, I believe two things do apply:
The women involved can sue in civil court for damages.
The testimony of women making accusations for which the SOL has expired can be used as evidence for a trial in a case for which the SOL has not expired. Shows pattern of behavior.
But I could be wrong about that part.
A civil case could turn into a class action suit...