We've also been rebelling against traditional values for over fifty years and even celebrating it in song and movies. We've adopted a utilitarian ethic in lieu of the traditional values we've rebelled against. I think those are more salient probable causes than over-crowding, especially since the reasoning given for over-crowding as a reason uses a utilitarian ethic (people are only good because they can afford do be). A large part of virtue is doing the good thing regardless of hard times or good times.