The one thing to remember about gays, metrosexuals, young professionals, and “style” conscious buyers, it that they are generally very fickle (Of course, I’m generalizing so please don’t take offense).
One day they are are in love with Downtown, the next day with Uptown, and the next day they want a house with a picket fence. When the income is there, they’ll buy but as soon as the income dries up, they need to dump the properties. That doesn’t prop up anything but cause the cycles of booms and busts.
Think of the new towers in Downtown San Diego. They are selling a “lifestyle.” What about in 15 years when those towers are ageing and when the now “stylish” lobbies and apartments are dated?
Relationship changes also cause owners to sell and take losses thus negatively affecting the market.