The chance that the enemy throws a fight or makes other mistakes that opens up new win conditions (or sometimes that simply one guy in the other team tilts and throws) is just too high in Dota in order to be able to call it quits after 10 minutes.
One of the main reasons for the toxicity in Dota in my opinion is that people don't understand that there are 10 variables in the field, but they can only control one of them. Don't even bother trying to influence the other 9 (apart from positive feedback/encouragement/communication to the team), it's a waste of time and only contributes to the toxicity.