Speed Academy has run a piece looking at why it's happening, one theory being that regular-guy owners are hopping on the runaway-price wagon without any good reason. As in the example of that high-mileage, scruffy 911 RS America at Bring a Trailer, the owner sees pristine examples valued by Hagerty at $170,000, and even though the average value is $93,238 he thinks something like, "Mine's got to be worth half of top dollar ..." The tide - even one rising on air - makes it hard to find decent prices.
Then there is the flood of money into the market. In spite of articles that try to temper investors' outlooks on collectible cars, other articles in places like the Financial Times and the Guardian promote vintage metal as a safe place to put money and reap astonishing returns.
Speed Academy thinks one side effect of high 911 prices is that responsible enthusiasts are turning their attention to cars like the BMW 2002, E30 M3, and E9 3.0CS, saying their prices are "sharply on the rise." The entire article is worth a read since it goes into markets far afield from pricey German steel, but incredibly, the entire piece was actually inspired by a 1997 Acura Integra R that sold for $43,000 on eBay. So while this could be the best time to get into the classic car market if you know what you're doing, it is certainly the best time to do your homework.