sustained falling home prices nationally

I'm not disagreeing with Tyler, but his comments made me think about the possibility of a U.S. real estate bubble, and the possibility that even without a real estate bubble/crash, we could experience sustained falling home prices nationally. But there really is no "national real estate market," since all real estate is local (and even varies within an individual zip code), and what is happening in Florida or Nevada could be much different than what is happening in Texas and Michigan.