At a maximum 5% increase per year, it takes 37 years for a $500 unit to catch up to the $3000 market price. So this law doesn't help that much with that particular case.
The example given is of a 500% increase in rent, by definition no rent control law should make such an increase possible in a short time frame.
Eg a law could allow any increase up to some benchmark, and up to 5% per year when above the benchmark.
(No clue whether that would be a good idea or not.)