I am pretty sure that most areas here in Portland affected by the shortage of parking aren't zoned to allow building a parking structure. I haven't looked this up though. Edit: It's not downtown here that has this problem, but smaller, hip neighborhoods where you have a shopping street surrounded by an ocean of SFHs

If high cost is the issue, it seems like people are complaining about lack of parking but don't want it enough to pay the real, unsubsidized price. So why should everyone else pay for them?