Why you think Blu-ray sales numbers have anything to do with this is beyond me. If that was a problem, Disney would either cut prices on the BDs or not make as many. Offering movies in an HD digital format won't make near the sales blip that cutting BD prices $5 would.
But on the 160GB ATV, you kinda have a point. I'm betting Apple didn't think two models was smart for something that gets the affection of a fox in a henhouse, and it needed a price break anyway. It needs much more than that, but beggars, choosers, etc.
I'm one of many hoping for a hardware revamp (not to mention the firmware) of the unit. It needs to be made large enough for an optical drive and standard 3.5" HDDs. Cost would be reduced if larger HDDs were used since those are cheaper per gigabyte than the 2.5" drives used in the current model. An optical drive makes the unit an instant competitor with BD and DVD players, depending on whether Apple finally joins the BD party.