Time is money and taxes are already amortized into any potential developer's math, regardless of what the rate nominally is. If the properties aren't economically developable in a "it costs us pennies to sit on them so we'll take our sweet time" paradigm then they're sure as shit not developable in a "I'm paying the same tax rate no matter what so I gotta put something up ASAP so I can a)get income b) sell" paradigm.