Greatest reason for Sony's success with the PS4

[Tamron]

It is simply a case of Sony having the most general popularity, at this point in time.

The success of the Xbox 360 was due to the launch timing and price, coupled with the slightly higher spec and more solid game lineup.
The success of the Wii was in getting non-gamers to buy in, even if they had no intention of staying, beyond these two instances Ninteno consoles generally have a relatively compact but dedicated following, Microsoft also has a compact but dedicated following, though their last console snagged a lot of "general" gamers.
Playstation has a decent chunk larger of a dedicated following but it's also better at attracting the "general" audience, just people that buy consoles for games and don't necessarilly care what brand that console is.

With that in mind the end of life sales for the current three consoles is dependant on which of the three do the best job of setting up and maintaining a solid framework to attract general gamers the best, it would seem, at this moment in time, that this accolade belongs to Playstation, but anyone making a call, right now, as to who will definitely come out on top is simply making estimations based on their own personal desires.

In short, we can say who is on top at any given point in time, but at a point where we are not even a year in to the lifetime of two of the three consoles, it's nieve to make grand assumptions.