It shifts priorities away from making the best product, to having the best marketing and product management. More money into marketing, that could be better used in making products better.
it's a chicken and egg problem.
Think of how much Aliens Colonial Marines sold on hype alone before the wall came tumbling down. Lot of disappointed Gamers, and virtually no word of the issues until the night before release if I'm remembering correctly. Thats dropping the ball big time, on everyone but the marketing department.