Actually, as posted in another thread, think it's because HD became so addicted to Sony-basher complaints about the early '06 proto-models (eg. no dual-layer disks, no upconverting), that they didn't notice the calendar changing, and didn't want to lose their one good act--
At first, they got that rush of confidence, but now, every time they try to resurrect "Uh...'PS3's can't do PnP'?" they've become the Kid Burping At the Table, who just can't get that sweet, sweet attention back anymore, no matter how hard they try.