You know I think the Xbox One not selling as much is not due to the PS4 so much but due to the Xbox360 and PC.
Think about it...
Decent with some big hits but it cost to much to start with, did not sell as well as hoped with a few issues from controllers with no rumble to start with and the big success of the 360.
A lot of the big games are coming to PC and have a better framerate and look better then even the current consoles. It is easy to buy a game from steam and others and play it.
Big success, I still got mine and games are still coming out on it. It has a massive install base ,online service and people have invested in it and a big library over along period.
The older consoles have had a longer life span then the ones before it and established themselves.
The Xbox one:
Now ignoring all the bad marketing etc that MS did , that will have course played some part to its sales BUT:
With all of the above in mind... Why do you need to get an xbox one? I don't. My Tv plays stuff and does heaps more then I need it to, I got a 360 but my PC is top end and I use a controller with it to play the top games on that.
And a lot of people will be in the same boat.. With the cost of the xbox one... Do you need to buy it yet?
Xbox live and features of the 360 were quite good and well polished already.
Now of course people love their PS3 but even for me I seen people who have loved the PS3 jump on PS4. PS3 and Sony have fans, but even those fans, from what I can see have always wanted it to be better in many areas. Sony has finally hit those problem points with the PS4 from interface, online features and more with a great price.
A lot more new and existing Sony PS Fans are jumping on the upgrade to get better and more, especially when it comes to the online experience.
So for me, I do not think its a simple matter that more are turning to PS4 then Xbox one.
I think you probably find there is heaps more still actively on the 360.