I think this subject has now been beat to death in the past, but as someone who has 50+ years of collecting ahead of him I've got say I'm not worried. If you look at the history of collecting anything you'll see that there are waves. 10 years ago a Schwinn Sting-Ray was worth maybe $150. 5 years ago the same bike would get $600+. Today the same bike is back around $300. It just depends what's in vogue at the time. I think right now is the heigth of "lightweight" collecting. You mark my words, in 10 years there will be half the number of people collecting "lightweight" stuff. It's basic economics of supply vs. demand at work.
In the art world you could buy a Rembrandt print (4th or 5th state) for what that deraileur is going for but not so 30 years ago. So if I look in comparison to that I'd take the print any day, but that's just me. Collecting is collecting and prices go up and down and fluxuate constantly depending on the factors of economics. Before you think things are too outragous with "classic" parts look at Comics 10 years ago and Guitars in the 80's. You'll see the same trends as the past proves the future. enjoy, Brandon"monkeyman"Ives
"Nobody can do everything, but if everybody did something everything would get done." Gil Scott-Heron