As real estate developers are generally thought of as having a wee bit of local political power, I imagine if the parking minimums had been problematic for them in the past that we would have seen some movement towards reducing them. I do think there has been a cultural shift (combined with the rise of car sharing) in places where being car free is possible such that more people are actually ditching the cars. When I first moved to Philadelphia "everybody" (as in, my peer group) had cars. Now they mostly don't. Before it made you a bit of a freak and now it doesn't.