"It's impossible to win if your (role here) feeds..."

It's really not.

I literally just played a game where my jungler fed every time he tried to gank, my mid roamed and always got five-manned, and my bot lane gave 8 deaths by the time their first tower fell (and that was pretty early). Stall to the late game I told em, and that's exactly what we did.

Enemy team got too confident, and we kept picking them off one by one while they were warding, capturing objectives, etc. Then we managed a win despite still being down eight kills by the end of the game.

The point I'm making here is that it doesn't matter how far down you are. If you pull your head out of your ass, you can find a win. We were down by the mid inhib, and only had inhib towers in top and bot. One nexus turret destroyed, the other with literally 10 hp. Surrender vote lost 3/2 in favor of quitting, then we managed to pick off the carries quick, secure nashor, and make one last push that they just couldn't recover from. I was the only one who didn't have a negative KDA all game and I didn't even end up being the one who carried us - it was our 0/10 Lee, 0/8 Ashe, and 0/8 Kayle pulling their heads out and managing some GREAT plays and isolating enemy carries.