I mostly play normals, so this isn't about ranked. I have lots of times where I as ADC can win lane hard, but cannot carry the game, simply because all the other lanes fed the enemy team.
It doesn't matter how much CS or kills I have. It doesn't matter how much wards I put down. It doesn't matter how much I help in teamfights, they just end up dying and it becomes like a MMORPG.
It's possible for all roles to go 1 vs 3+ if they are fed enough, but no... ADC needs team members to play with.
All I keep doing is farming, warding (also denying vision) and going for objectives. Taking turrets and pushing the minion waves in all the lanes.
In my previous game I went 8/0 in bot lane easily and took their turret, but top lane fed the sh*t out of Morde. Amumu fed horrible and Kass was evenly. We lost in the end.
It would be nice if Riot made ADC less team reliant, because carrying as an ADC only seems a thing for the mechanic Gods.
**Extra note: Oh, I know some of you will tell me how easy it is the carry as an ADC, but I guess most of you get a premade support, so ofcourse it's easier to carry a game.**