unless they surrender ridiculousy early, I disagree
What is there to disagree with?
In single player, if you quit, the game ends. If you surrender, the game ends. No difference. There's nothing to disagree with on this point.
Perhaps you disagree that it sucks in multiplayer. If your the player who quits or surrenders, either way, the game is over for you. It's a different matter for your team mates though. Most likely your team mates would like having an AI take over for you.
Would you rather have your quitting allies replace by an AI or just sit there and do nothing the whole game?