The biggest reason in my opinion is simply that PLaystation is the biggest brand and as long as they don't fuck it up like they did with the PS3 price the first years, they will sell much more consoles by default.
There are so many people who bought a 360 instead of a PS3 just because it released much earlier (especially in Europe) and because the PS3 price was so high that they simply chose the 360 because most games were the same on both consoles. All these people have no reason to chose something else as a PS4 this time around.
Even before all the console reveals, Microsoft mistakes and low Wii U sales it was pretty clear to me that PS4 will easily sell the most as long as the price and time of launch will be comparable to the competition.







