There is one simple thing every player needs to realize at some point in order to get good at this game and that is, my team mates don't matter. Team mates matters for one game, it is possible to lose a game because of a team mate, be it mistakes, leaving the game, trolling, feeding on purpose. And you can blame a team mate for losing one game. However, you cannot say your team mates stops you from climbing all together. With that logic i could just as easily say, when you reached silver in one week you got there because of your team mates.
Now there are two ways to play this game, you can rely on luck or on your own skill. If you perform average every game, you barely make plays but you don't really die either, the result of the game will be decided by your team mates abilities to make plays and winning decisions, if you play that way, you rely on luck and you rely on your team mates to carry you. Now if you play this way, you will never ever get high elo, you might climb a few divisions, but it will eventually balance itself out with poor team mates on your team.
Let's assume you play bot lane as a support, for you it will be a 50/50 whether or not your mid laner wins or loses the lane, now if you leave him alone you rely totally on him alone to win his lane and 50% of the time he will lose. Now, how could you improve those chances? You could roam mid, try to get a kill or relieve the pressure, you could place wards around mid to help him against jungle ganks, you could take down the bot turret, rotate mid and take that turret to give your team some global gold. Doing those things are what will give your team a better chance of winning and that is what carrying is. The more of those plays you can pull off in a game the better your teams chances of winning and then you can climb.
Now if you're a mid laner, you have the power to roam bot lane, grab a kill or two and then get dragon, benefits your whole team.
My point is, if you want to rely on luck and on your team mates then just play the way you play right now, but if you want to actually climb, stop blaming your team mates for dying and instead ask yourself, what could i have done to prevent them from losing the lane?