Leaver Gold System?

Recently I have played a ranked game where the mid laner Lux disconnected her game with a 1 kill 5 death score, having fed both Zed and jungle Nocturne. This happened at the 15 minute mark and I have told my team to Forfeit the match at the 20 minute mark.

HOWEVER because I was supporting a jinx and we were doing good in the bottom lane, the jinx insisted everyone to stay and try to win the game. To this i kept asking for a forfeit throughout the game for several reasons: Massive gold difference between teams, Harder to contest objectives, Less ability to stop split pushes.

This is what I am asking

Why is there no leaver gold system in place, that will lock out a AFK player from rejoining the game after 5 minutes? At this point all the over time gold the AFK player had accumulated should be split between the remaining players, as well as 20% increase in over time gold.