If you think about it, MS is actually pretty smart with their timing in anouncing this.
I can only speak for the Netherlands, but in the last two weeks all major retailers here have anounced that anyone who hasn't pre-ordered a PS4 yet won't get one until 2014. So even if a lot of angry people now are saying "screw MS, I'll buy a PS4 instead", fact is they will still have to wait until 2014 for a next gen console and by that time the Xbox One will probably launch here as well and then suddenly you have to make that choice again: PS4 or Xbox One. And my guess is that when that time arrives 4-6 months from now, a lot of people will go back to their original choice of Xbox One and have forgotten about all the anger they are feeling now, so MS won't have lost all that much sales anyways.
I'm glad I paid my downpayment for my PS4 preorder today guaranteeing me launchday goodness, but I feel bad for all the Xbox One fans who are getting double screwed (no PS4 or Xbox One this year).