I think you make a good point. Even with "finished" games--if a developer rushes a game's release and there are still bugs, players will lambast it with their reviews. Even after updates fix these problems, the taint of the initial negativity still seems to cling to the game.
Game developers must really be searching for ways to finance their work. Pledges, pre-orders, extra content, etc. It's the plight of many creative endeavors, I guess.