driving hype. the announcement in the first place was to deflect from the negative press about their financial stuff. this will be the first sunday since then that they could show the stuff. doing it last week wouldn't have overcompensated for their financial reports, and waiting till this sunday wouldn't have helped them either.
I think this was supposed to be a big E3 reveal, but because of the financial report blowing up, they decided to talk about it early.