I don't own any, but I think it'll be around for a while.
Reasoned thusly: Oil is likely to stay at or over $100 /bbl. The price of asphalt, according to this article from July's Denver Business Journal (and others, that popped up on le goog), is very sensitive to the price of oil. Around here some county highway departments are deferring maintenance on back roads or beginning to discuss converting them to gravel or dirt.
Failing that, it may be realized that cement provides less rolling resistance than pavement, and sections of state & federal highways may be converted to sectioned concrete - just like the last time (back in the 70's). Thumpthumpthump...

So... The guy who wants to train on deserted roads but still ride a raceworthy bike, may very well find himself buying a set of long reach brakes and 650B wheels and save the "good" wheels for actual racing. Nobody's really going to put a lot of dirt road miles on $1000 wheelsets with 140 psi tires. 650B (or 650A, for that matter) makes sense, as you ought to be able to run a much wider tire than you would with 700C, yet still use the same frame. My understanding is that some of the 650B proponents use them extensively on gravel and fire roads.

The argument about comfort presumes a certain level of maintenance on the roads in question. Should that road become semi-permanently awash in chip seal or becomes a series of cement slabs, narrow 700C tires will become the boutique size.

At least that's what my magic 8 ball is sayin' tonight. Check tomorrow for an entirely different perspective.