The entire vintage car market seems to be riding a bubble that is being pulled upwards. What we're seeing is a lot of the Baby Boomers hitting retirement age with more disposable income than any other generation hitting retirement in history. Now that they have time on their hands, they are snapping up the toys they remember from their youth. Even the LBC world can't escape the bubble. Big Healeys are pulling down crazy money, which is pulling up the MGA market, which pulls up the Bugeye market, which is pulling up the Spridget market as an example. The car I bought 2 years ago could easily be sold for $2000 more than what I paid for it in the same condition, let alone what I've done to the car since.
I've often asked the question, are Porsche 911s really THAT good? As in $100,000 worth of good?
If you want to see what happens when the bubble bursts, go look at the used airplane market. There's always going to be a demand for warbirds, but your run-of-the-mill GA aircraft are incredibly inexpensive. You can get yourself into a decent Cessna 172 for about $20,000 that is about a mid-time airframe. The number of private pilots who were trained by the military has been dwindling since the World War II / Korea generation for the most part aged out of flying, and the cost of learning to fly is prohibitive for most people. The result is there are more airplanes out there than people willing to purchase them.