Leavers and its effect

So I've gotten back into league lately and decided to climb the ranks again. Things have been decently fun and I've even met a couple of really cool players, however, gaining and/or even maintaining LP has been the most difficult thing ever for me. Now I've always felt like luck has played WAY too big of a role in ranked mode, but now-a-days, it seems to be a more prominent factor than skill and knowledge of game mechanics...which, in my opinion, is a terrible model for elongated competition. In the past week or so, I've had approx seven leavers.

SEVEN. LEAVERS.

IN RANKED.

And it's always for various reasons, too. My most recent one was this supposed platinum smurf who had gotten the support role in champ select. He had said something along the lines of "I'm a plat smurf so if you guys want an ez win trade me a carry role". No one said a thing, after all it didn't sound like an ultimatum. He said "ok" and I lol'd. He then proceeded to pick Gangplank to "support" our Vayne. Still, no one called him out. Needless to say, his performance was less than optimal and less than five minutes in, he afk'd and our Vayne got thrashed. The rest of us did what we could to help, but alas, it wasn't enough to rectify the imbalance. GP ended up reconnecting around the 15 minute mark and his initial excuse was "I went to get dinner" followed by "well I told you guys to give me a carry role". ...yeah. Okay then. Onto the next one. Some of the other leavers I've had got legitimately randomly disconnected. Which sucks, but hey...it happens. Seemingly often. Another got pissed and left because he couldn't get blue buff at the beginning of the match (was a mid laner, for clarification). And some players just troll champ select and don't even connect.

So what is up with all the leavers lately? Why isn't there a reliable system to balance out these 4v5s/3v5s?

TL;DR

The point I'm trying to make is, League of Legends has been out for a little over six years and there seems to be zero progress towards an actual solution for victims in a game where other players leave / don't connect. Why is that? What's Riot afraid of? What are your opinions? What are your suggestion(s)? What are the arguments for and against?