Others have mentioned the unfairness of asking taxpayers to subsidize drivers. This is particularly egregious in Midtown Manhattan where many taxpayers are not drivers and many drivers are not (local) taxpayers.

But even as a driver I prefer when cities place an efficient price on parking. Otherwise, if parking is too cheap compared to demand it costs time and stress circling the block to find a place to park. Market pricing, where the city sets whatever prices are necessary to maintain an empty spot or two on each block, seems more fair, efficient, and pleasant.

Why should everyone pay equally, rather than people that currently store their private property for free on public land in some of the most expensive real estate in the country?

The point wasn't supposed to be to raise more money, it was to decrease the amount of people using the roads. Taxing more would, if anything, incentivize people to use those parking spots to "get their money's worth." More realistically, it would not add a barrier to actually parking on a day-to-day basis. Making you think about and reconsider it every time you go to do it with the paywall is what they want (and what is arguably necessary in order to fix the underlying problem, unless those tax dollars are going to go towards multi-level parking garages that add spaces and not just the existing roads).

It’s kind of how I feel about rent too. Instead of paywalling this $7k/mo apartment maybe just tax everyone a fair amount?