A bit of chicken and egg here. To some extent it's true. But collectibility also involves desirability. It's when desirability and rarity collide that the prices go through the roof. There are a lot of very rare bikes that aren't all that well known that go for relatively little money compared to their quality. On the other hand, prices for nice Schwinn Paramounts remain strong because a lot of folks would like to own one (and coveted them years ago). Yet Paramounts are dime-a-dozen compared to many other makes. Take marques like Galmozzi or Gillott, for example, that are relatively rare, yet didn't fetch good money until people caught on within the recent past. In addition to rarity and desirability, there's also the issue of opportunity. For example, it's well known that there are a relatively very small number of Confentes in existance. Yet in the short time I've been following and collecting vintage bikes (since maybe 2004), I've seen maybe a half dozen available for sale. In other words, if I wanted one and had the money, I could have obtained one by now - they circulate. Eisentraut A frames, OTOH, don't, despite the fact that many more were produced than Confentes. So Confentes are certainly very "rare" in one sense; not so "rare" in the sense of "I'd better buy this one or there may not be another one along in my lifetime." But the perception is that they are both very rare and very desirable, and prices certainly remain very strong.