There is another factor here and one that is more subtle, peer-pressure.
If you hate/enjoy a game that has been praised/slammed in all the major outlets are you going to trust your own judgement, put your neck on the line, and submit a review to your editor that bucks the trend? Or are you going to play it safe and follow the herd? What if your review risks angering a major advertiser, are you still so sure that you are only one who has been able to truly see that game for what it really is?
I've seen games where an early review has contained a factual error that has been repeated in other reviews by other reviewers (it was about a feature that was "missing" but was actually pretty easy to find in the menus). I don't think people were deliberately copying the early reviews but having read a "fact", they just assumed it was true and didn't look for themselves. And if that holds true for objective things like menu items, what about subjective things like "there are too many cutscenes" or "the pace of the game is a bit too slow". It's very easy to be swayed, and little things can easily pick up momentum.