5v1 at level 6 works. I suggest you watch youtube videos on how to do it effectively. I consistently help my team get better and the games I can hlp that 1/10 guy out and turn his game around to 11/12 is a great feeling and typically helps me win. Is it every time? No. Can it be done? Of course. The MMR is set up so that a majority of players ARE at their skill level and playing against their skill level. Look up the real numbers for each rank. Statistics don't lie unless you manipulate them. When there's a possible 120 cs at 10 minutes and you are an ADC and have only 50 cs, EVEN IF IT'S THE HIGHEST IN YOUR GAME, you're doing something wrong. If your team isn't contesting a dragon by 9-10 minutes in, there's something wrong. If your mid laner is getting camped and bot or top and jg aren't coming to counter it, there's something wrong.
You assume, wrongly I think, that there are trolls that you have for most of your team mates. This isn't true. Most players I feel get discouraged when behind. It's VERY hard to recover and teams beating up on them instead of helping them get better just makes it worse. Accept that you're not better than them and it's your ego that thinks you're better. Go watch youtube and check out mobafire. Get better at watching the map and responding to team mates that need help. Learn how to use champions mechanics to out play people in your MMR so that you can help your team more.
Believe me, I know I'm discouraged when my top goes 1/10 and I come out of laning 7/1 with 190 cs as an adc and can't seem to get the team to pull it together. But as long as people are trying I try to help them. I try to make the game fun. Doesn't seem like you do that or understand the value in it.