Canada

Yes, provinces and federal government can help, but municipalities can solve things quicker.

Municipalities are a creation of the province. Everything municipalities can do, so can the province. With that, the province can actually get things done quicker here as they can force the changes across the entire province at the same time.

Primary mass transit would be expanded to increase the feasible housing areas

It's pretty clear that access to mass transit increases the value of homes, sharply. Removing access to mass transit would be the quickest way to see housing nosedive back to affordable levels. Housing has become much more expensive because living in them has improved dramatically over the past couple of decades. Expansion and advancement of mass transit systems is one of features that has contributed to that improved livability. It is a truism that desirable things are more expensive than undesirable things.