The prices were dropping, like the HD4000 line was when the HD5000 line came out, but this bitmining gimick...
basically made the HD6990 all but impossible to find for a long time (after they barely came back into stock, after the GTX590's launch). HD5000 cards, with their sheer ALU count, had insane resell values that simply were ridiculous for a previous gen GPU. Uptil recently, the HD5870 was going to 300usd or so, used!!*
*by going upto, I don't mean, "upto," just, "it was commonly seen at ____USD."
I don't really know anything about bitmining, but isn't it a huge waste of resources? Like, costs more money in electricity than you make?