CassidyIzABeast
Member
I'm gonna guess that Microsoft was anticipating the new line of consoles to launch next year. Sony, at some point in the last 12 months, decided it was going to bring it forward and Microsoft were left twiddling thumbs. They are easily the most reactive, major software/tech company, around at the moment.
Microsoft has beta dev kits out in the wild according to Thuway. That means they've been planning a 2013 launch since before the ps4 announcement at the minimum.