Not many collectors that I know actually have the patience that we all know, deep down, could save us some scratch. But with Kubricks, you sometimes really don't know when something will pop up on eBay again. As you mention, some figures exist in small quantities, but this is exacerbated by the fact that these figures typically have to either be imported or sold by a foreign seller (in Hong Kong or Japan, typically). And with some of the lines that are not popular outside of Japan, you just may not see more than one or two auctions in a given month.
So, unlike what you see with more popular lines of toys, I personally have a tendency to over-react, and to pay more than I should for certain Kubrick stuff. The Star Wars Kubs are relatively easy to find (compared to some other Kubrick lines), but even there, I have seen only 2 regular C-3POs over the last month--one in a lot of series 3 figs, and one that ended today. I think others exercise the same amount of overzealousness that I often do, as indicated by the fact that today's 3PO went for $40 (sadly, I didn't win
But back to Yoda and some others, the absurd thing is that I actually don't see that price as being unreasonable. When the supply is so low, and when they are so hard to get a hold of, $130 actually becomes reasonable. . .for a 2 1/2 inch toy that was just released. It is not irrational to place such a value on these things, but it is crazy as hell, in my opinion.