I don't see PS4 ever dropping below 100K, not until it stops getting supported by Sony, definitely not a single week next year, I think it's at least 2 years away from it's peak sales period too.
I think LordLichtenstein (not sure about spelling :O) made a thread about PS4 not selling less than 180K each week next year, I agree with it for the most part, except for maybe the first week of Jan, where there isn't much coming out, but the system has the official China launch in mid Jan, tonnes of new quality exclusives coming, GOW, GT, Uncharted, tonnes of new IPs we haven't even heard of yet, new games from old IPs, the possibility of games like Agent and TLG all of those games maybe dropping on PS4 in 2016 onwards that makes it almost impossible that the platform will drop below 100K.
I think as an absolute baseline for 2015 weeks the lowest it will go is 175K, once it hits it's stride after Jan and the big games start coming I'd be shocked if it went below 190K.
