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.
It's been ages since I've driven there, but SFpark[1] was (and maybe still is?) considered the gold standard in demand-based pricing.
One interesting finding from the initial research reports was that it achieved the goal of improving availability while at the same time lowering the average meter price, which is nice because it drives home that the purpose is maximizing efficiency, not revenue.
And despite my using it as an example above, Midtown Manhattan actually does this reasonably well, especially in contrast with trying to park in the Upper East/West Side or Harlem.
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).
Please no. Just tax me at the end of the year if you really need more money. Stop paywalling everything.