> Most of Manhattan apparently has <1% annual property tax, and the eclectic sometimes regressive way it's calculated in NYC is suggestive of corruption.

While NYC has never lacked for rot and corruption, those really aren't needed - or even particularly useful - for something like this.

As soon as you've got any sort of law / regulation / status quo that benefits a class of well-to-do people, there will be intense pressure to maintain that situation. Vs. the opposition - honest reformers, idealists, the poor, whoever - even if they're far more numerous, just never seem to have the zeal / focus / attention span / whatever to correct the problem.