I think it might be that people who are so worried about mmr that they won't even pass a remake in hope of an easy win aren't the best players to begin with.
Also the people who don't pass it in hopes of a free win are more likely to get upset when it turns out not to be a free win, while the other team's morale will be bolstered by seeing that they could possibly turn the game around on them.
You're all wrong. The reason behind the four winning all the time is simply because of the economical advantages.
One less player also benefits the team morally, one less problem when it comes to the team synergy.