If you have the right Stern games in your collection that you bought HUO after shopping carefully in the past two years you are probably safe from depreciation to the the high costs of the new games, the lack of finished code on the new games and the obvious manufacturing quality problems in the past two years.
The guys paying $9000 for new games are probably going to take a depreciation hit, but the high prices for new games will probably push many pinheads towards nice HUO games. Hence, prices on them will probably stay steady or increase.