An Idea to make League of Legends more fair

I know many of you may have different opinions than me, but after being slightly frustrated because of losing my promos to back-to-back 4v5s, I had an idea to eliminate some of the unfairness in League of Legends.

I think a loss forgiven should be given to the remaining members of the losing team if a teammate is disconnected for a set amount of time (15 or 20 minutes would be good I think). This way people would not lose elo to teammates not connecting at all, or rage-quitting after 5 minutes (we all know those junglers who quit because of a bad leash, or the laners who quit after being 0/3 at 5 minutes). The reason they should only see loss forgiven if a teammate is gone for a certain time period or longer would be to prevent a potential problem of people quitting after they already know they will lose the game, because at that point the game should be over in the next 10 or so minutes, so quitting at that point would not reward your team in any way. This would prevent players from telling their teammates to quit at the end for a chance for loss forgiven.

If you have any questions about my idea ( I know I'm not great at explaining), or potential flaws in the concept, or maybe just agree with me, please say so in the comments and I will try to answer questions.