but it does matter, boosters exist and they need to consistently be able to reach the ELO's required, on call, quickly and evidently they can.
in this regard smurfs also achieve there desired ELO easily, for instance you dont see high ELO players stuck in low ELO thats because they are both individually better and better at controlling the map.
stop focusing so much on fighting and more about objectives, push more and take something, if your team for example is fighting on one side of the map and you won't get there in time to either A) win the fight out B)clean up, dont bother ignore the flame push and take a turret or two they are then forced to back and defend or lose more objectives, atleast 1-2 will recall, rotate and push another lane/dragon or clear the enemy jungle or simply back and defend the best you can.
focus less on you and less on killing and more on the map. i did this last season in flex solo (i usually duo) and i went from S5 > G4 as jungle so i could push and be obnoxious in pushing and would of gone higher if i didn't have a newborn and had fatherly duties to attend to.