I don't know that I agree that the price of "rare" vintage bikes & parts will always go up. People tend to collect the things they wanted but couldn't afford, or had when they were younger. Hence the average age on the list and the popularity of NR/SR era stuff. I have wondered if the prices would suffer as we baby boomers croak. There will always be a collecting audience but how much smaller will it be? Remember the indexed shifting/brifter stuff that is OT to us will be vintage to some later generation. Maybe I should stock up on some NOS carbon fiber frames now since they probably won't age as well as steel frames!
An analogous area might be car collecting. I believe that 60's muscle cars are now popular and prices have risen. I wonder what has happened to prices of pre WW2 and 1950's cars?
Len Diamond
Ridgewood, NJ USA