Not sure where you got your statistics from but you need to reconsider people who live in Manhattan vs the rest of the boroughs. People who own cars in Manhattan are often pretty wealthy, because it's much more expensive there to own one, as you will need to use parking garages. But in the other boroughs? That is not quite the case. The majority of people I know with cars (all outside Manhattan) are not earning that much. And many who do own cars here go for cheap, used, but reliable cars that don't cost anywhere near 12-15k per year, not even close. In some parts of these outer boroughs, public transit is either nonexistent, slow, or unreliable. Even with traffic, driving is often faster.

People are not entitled to store private property on public space, but when transportation systems are setup a certain way, we expect certain things. If you want to reduce car usage, you need to provide better alternatives. Other major cities are doing so much better with their subways. But NYC continues to ignore subway expansion in the outer boroughs. And subways in my opinion are the most efficient method of travel in a city and should be the #1 priority in transportation. More than buses and biking.