Personally, and I am certainly no expert, I would expect prices to hold pretty stable about that mark for a while. When GW stopped production, all prices shot up, and people were looking to fill some very specific holes in their fleets. Now we are at a point where there is no supply, but most people have what they need and new players are not interested in paying those prices. As supply becomes even more difficult on the second hand market, the price will probably rise, but I suspect that this will happen slowly, and will be counteracted by people just selling their fleets and getting out of the game.
Personally, I would recommend that all new players find an alternative company for these that still produces spacecraft minis, and put together an 'alternative counts as' list and just go with that, unless you really do love the BFG designs.