Does lower gas prices= Lower MB diesel and VW TDI prices?

Just curious on what ya'll thought on this. My thought is that once gas prices go back down, people won't have as much of a demand for these cars, and they won't want to pay the higher diesel costs, so the prices will drop back down to what they were a few years ago. I have a potential buyer for my Bug, so that will free up some parking space at my house, and I might consider getting another MB diesel, if I can find a reasonably priced one, or, if I also deciede to sell my truck too, I might consider getting something with and OM606, or even a VW TDI, as long as the insurance rates are less than my truck, which I feel are way to high

If I don't end up with another MB diesel, I'll probally get a Volvo or another Subaru(this time without a turbo).