People leaving games saying they have other accounts to play on

Leaving games has become much more prevalent this season in my experience and i am fed up with it. I do not understand the weak mental of this region and the lack of punishment is very apparent by riot games. of the people i have reported that have left games, and i have kept an excel spread sheet with their names, i have only gotten an instant feed back report on 3 of the 15 i have had since keeping the list. i have no idea what riot is doing to counter act this but the system in place is broken and out dated, the punishments are just insufficient. also can we not let people who haven't played on an account for more than 3 weeks not play ranked until they play a certain amount of games in other modes. it makes no sense to me that i have been hard core grinding and someone who has not played in 3 months decides to play a game of ranked league of legends, and i get stuck with them on my team and they utterly just feed. How does that make the game fair and balanced? im not saying this trying to get my LP back or complain, but everyone needs to be questioning why we have to deal with certain nuisances and annoying parts of the game, and riot does nothing to try and fix them.