Where do console developer units end up?

[Zaxxon]

I've only seen a couple real console developer units for sale on Ebay and elsewhere, 3DO and Jaguar units. I suspect it's because both of these companies are completely out of business. There are other systems dev units that I've never seen for sale like PSX(not yaroze), TG-16, SNES, NES, Saturn, 32X, Genesis etc.. What happens to these units when no one is developing for the system anymore? Do the companies make the developers return them or are they free to keep them/sell them? Why would Nintendo/Sega etc. care?

[DogP]

Well... I don't think the companies are supposed to get rid of them... I've seen companies that still have some old dev kits... but I know some people take them and sell them to collectors/homebrew developers... I have a Virtual Boy development kit that I'm borrowing from a friend who is a collector... and I know of other people that have official dev kits that got them in pretty much the same way...

DogP