AFKs?

Hi there. I have a question I was hoping someone would be able to answer.

For the second time in a row now, I've lost the very last game of my promos due to an AFK. I don't mean someone got stomped in lane and then left (which is lame) or D/C'd halfway through the game (Also lame)

I mean that from start to finish, they never connected. Not a single step with their character. They were 100% gone the entire game, from the first second to the nexus blowing up.

What I don't understand is why there isn't some sort of detection system for this. Why do we still get it counted as a loss in promos, or a loss at all, when a player legitimately never connected. Instead its just saying "Welp enjoy your almost certain loss" to people in promotion series. I get that 4v5s are still winnable, and I certainly tried my best during those games, but in the end it was simply too much to overcome. And this is the second series I've lost because of someone not connecting for the ENTIRE game.

Why hasn't Riot done something to make a loss forgiven if someone is afk for more than 15 minutes or a game, or something similar? Anything to give the people who are forced to deal with an AFK teammate a little slack. You don't even gain any benefits in game for having an afk player. It just seems like its a recipe designed to make a team lose, and make sure they're all upset about it afterwards.

Can someone explain, is there a delicate system of balance that prevents this? Or is it not being implemented because Riot is too concerned with Esports and doesn't care about the normal ranked queues?