Mr_No on 09 April 2015
One of the reasons for this has to do with brand loyalty. They've found enjoyment on that console and they trust the company. So maybe they don't see why to move to the other one. People want their consoles to do great and want exclusives so the other camp gets jealous and salivates over it. More sales on their consoles means more recognition and many more games in the future. Of course, profiting is an important part of the latter, but that's another topic.
