Rising Tide Lifts All Boats, But . . .

[nat]

Supply and demand curves are often non-linear. To take one dramatic example: if there was only one telephone, there would be no demand for it, and (up to a point), demand increases as supply increases. (Because the value of having a phone depends on being able to talk to other people on it.)

And yeah, that t206s, and 33 Goudeys, and a lot of the other valuable sets are valuable depends, in part, on them being relatively common and widely available. Trying to build a very very rare set is difficult enough that lots of people aren't going to try it. And while trying to complete the monster is also really difficult, you can at least make progress on it pretty easily. So lots of people try to. Which produces the demand, hence, the prices, despite the easy availability.