I would love if (_consistently available_) $15/day street parking was a thing in Manhattan, it'd be a good deal cheaper than garages and obviously a lot more convenient than keeping your car elsewhere. There isn't much benefit to having a car in Manhattan for day-to-day life, but it would be nice to have for things like day trips. Right now I park my car about 45 minutes away in another borough (at my family's house) so when I do need to drive I have a +90min fixed cost added to my commute time.

FWIW, Manhattan commercial real estate goes for about $80/ft²/yr. A parking space therefore costs about $40/day in real estate rent, so $15/day is well below costs.

Is that $80/ft^2/yr raw land value? Indoor space cannot be directly compared against a spot in a garage that’s not climate controlled and is more vulnerable to vandalism.

For more on this solution read The High Cost of Free Parking by Donald Shoup.