Well, not saying that this is everybody, but there are going to be people out there who went 360 last gen, made a kneejerk reaction to follow everybody else they know on the internet and in person to switch to Playstation, then realize after DRM reversal that they may have made a mistake. Honestly, if you use Reddit as a case study, you'd find that E3 was when most anti-MS posts got the most support, then it kind of lulled down until the DRM reversal, when people try to justify switching over by posting and upvoting things about lower powered X1 and higher price, etc. Even now I know people who went PS4 and are really anti-X1 but struggle to explain why they went PS4 in the first place, especially when they could afford either or didn't really care about graphics in the past.
Now, I'm not saying the X1 doesn't have faults in higher price and less power, but there definitely are people who normally wouldn't care about that but suddenly do, because they suddenly realized they preordered a console that had a brand they never supported before and on top of it didn't have that much compelling to offer at launch.
Edit: Personally, if each console had been on the same playing field, same price, same specs, no DRM stuff, etc., I think both consoles would have 4 million sales just from supporters and their first Christmas. I think because MS fucked up so bad, X1 fell down to about 3 million guaranteed sales and PS4 went up to 5 million guaranteed sales, at the very least. For all we know the split could be 4 and 6.