As for public interest. The idea is that without regulation, new apartments and condos would choose not build parking pushing their residents to park on the street. This causes congestion (cars circling trying to find parking) and makes going to these areas less pleasant. And I'm sure some would say these regulations remove preexisting subsidies, since they prevent new developments from using city streets as their parking lot.
How do these other countries deal with the lack of parking? I think simply suggesting better public transportation and redesigned cities does not solve problems that people are having right now.