I believe it is because they realized people are generally stupid. With that knowledge, instead of making a PlayStation that was the most bad ass peice of tech on the planet, they went with a simple device that is by far the worst PlayStation ever at release, and offered nothing that simpletons find scary or unnecessary. Now that they got the simple minded to buy into it, they can start to slowly add to the platform to make it an actual worth while device.

To be honest, I am glad that something finally worked out. Even if they had to lower themselves to what PS4 is in comparison to previous PlayStation consoles, at least now that they are back on top they can start to innovate again. I hope PlayStation Vue turns into the succes it should be, and that the simple minded will not turn their backs on Sony again as they start to slowly try and lay the foundation to an amazing future in electronics, software, and networking.

they're not winning. haven't you seen the last NPD?

It's so much that they're doing anything special, it's just that they haven't screwed up as badly as the other two guys.

NPD is not Global.

 Well said. The only thing I would change is...

"They never tried to add or remove anything, just gave exactly what is expected of a playstation console and are being rewarded for that".

Playstation consoles always start out slow and pick up pace later on. It honestly difficult to tell how good the console will be compared to others until later in the gen. 

Different can work and be fun, but if you're not careful, you might pull something/get hurt/have to go to the ER. <-- tortured metaphor

All of the above.

Because of 1,2 and 5 in the poll :p

Out of he choices I went with better marketing(well more like better Branding).
However the main reason is it has the best Hardware, and people want to play games on the console that looks the best.