I have got to accept it in time, people sometimes leave or rage quit, and they should be punished, if you aren't playing ranked I think it shouldn't be a big deal of it, one left too bad just give up at the earliest possible since that disadvantage can't be in the majority of the time overcome.
If you are playing ranked then it changes everything since you are losing ELO and in some cases, if cryptocurrencies get into the games you will start losing money or stop earning it, just because someone decided to quit or not play.
There is no cut clear solution to this problem, and you present an intriguing one, but I think it wouldn't be fair to the player that gets pushed to the side just because someone decided to leave.
My position would be if someone DC then, first punish him hard, like demoted or don't let them play ranked for a week or something harsh.
Second, let the team chose to surrender or keep playing, if they surrender then let it be so they don't lose Elo nor anything just like nothing had happened if they don't give them an incentive, double the reward of the manage to win and half the loses if they lose.
Whatever is the best solution this has to be taken care of since, it is a problem. Thanks for posting.
The problem is when you get punished for a dc that is not your fault.
I like the surrender idea, maybe they can lose less points the earlier they do it.