But they already mostly do. In far-out suburbs, huge mall parking lots aren't competing with anything else, there's plenty of space.
And in downtown cities, parking garages are alreay expensive. $30-50/day in Manhattan, for example. (I would agree that street parking should match garage rates, and not be effectively subsidized, though.)
That seems pretty cheap. How much is rent on a similar amount of space? Remember all the space needed for accessing the spot, administration (if any), too! Or are there different rules for storing cars than people?
(Incidentally, there very much are different rules, and for the most part US cities have worked very, very hard to make it easier to add cars than people).
Well, at $5/sq ft/mo. for average real estate (Manhattan, e.g. a 600 sq ft apt is $3K/mo), and if a parking space is 180 ft, then that's $900/mo., or $30/day, plus overhead/access.
So $30-50/day seems right, especially considering parking garages tend to be underground, no plumbing, etc., so the space is presumably cheaper than residential/office.