I also receive a number of real estate listing from Red Fin every day to find out what homes are selling for in my area. I have yet to see a single home with a pair of floor standing speakers in a room. This includes homes priced over $6 million. This said, do less than 1% buy sound systems. I also see TV's and not a single TV has surround speakers.
@larry5729, it's impossible to make any judgement based on real estate sales photos, because the property is often professionally staged for sale. That means emptying the house, doing cosmetic things like cleaning, painting and new window shades, and bringing in nice, clean furniture for show (and the sellers have already moved out). Staging with floor standers and surround isn't going to help sell the property.
That said, there is nobody in my personal life (co-workers, friends, neighbors, extended family) with a nice audio or surround setup. I would say that less than 0.1% care enough to spend money on it.