I disagree:
...
So I definitely think it is the most plausible explanation we have for the swing in the US.
I think you misread my post. In the end, we can only speculate, as there is no way of knowing (for us) who is buying these next-gen consoles en masse (and who isn't). I'm essentially on the same side, but I don't think a singular 'plausible explenation' covers all angles. The market is big and diverse - and many have different reasons for upgrading.
PS4 selling at a higher rate could for all we know, be down to the great PR they've been receiving in combination with the lower price. The US has always seemed to be more price sensitive towards new consoles - where as in Europe, we tend to pay a lot more for these things. So the $399 price advantage of the PS4 over the original price point of $499 for the Xbox might have been a bigger factor then we might give credit for. Then there's the whole point about the inclusion of Kinect and the focus on TV. This sort of stuff is probably not in line with what the most hardcore gamers wanted to see (the ones that rush out to buy new consoles when they come out).
I'm not necessarely convinced the loyal brand supporter (who make out a substantial part of early adopters) would just run out and buy the next other console on the market - not when they have invested considerably into a platform, are likely to have many friends on their friendslist and share lots of play time together. So IMO - these people either bought a Xbox One despite the ongoing negativity (and are happy with their product none-the-less) or they might be inclined to wait - wait to see what happens, how the market unfolds etc.
Essentially, as I said, I agree that there is a 'swing' - I just find the fact that Destiny sales are leading on the PS4 to be more telling than any basic sales figures showing that the PS4 is simply selling more.
We're all speculating here. Note that the above and my post mainly refers to the US market, since that's where the Xbox has been focusing its sales and where their largest/strongest market is. I've always considered Europe to be in favour of the PlayStation brand as whole, so PS4 leading sales in those territory is not a big surprise IMO. It's the US market that is interesting, because that's where the X360 has outsold the PS3 considerably and where PS4 now is leading.