I'm sure they'll patch it to somehow make the uh.... "campaign" playable offline. Doesn't make any sense otherwise.
Idk if Gamespot has posted a review or not but their article Monday pretty much nailed it for me. Polyphony seems to be moving the franchise in a direction that caters to a minority of players. But if GT5 could be as meh as it was and still sell on name alone, this probably will too.