It's just that runes have really polarized bot lane. Your "feeders" probably aren't actually feeders. They are bad communicators or slow to react to their duo lane.
For example, my Plat I partner last night was behaving erratic, probably sleepy, but wanted to play. Got into game with him as Morgana Support vs Tristana/Shaco. I traded kills with their Rengar jungle level 1, who dove turret to kill me after his team invaded. My duo literally recalled rather than peeling me, or I would have had FB and not died.
Then, in lane, Shaco was horribly out of position, got Q rooted three times, and on the second time, actually dropped to 1-5 HP. My duo took 5-6 seconds to decide to go in, by which time Shaco just Decieved out, and Tristana had been poking me while I'm trying to kill Shaco. I Q'd Trist; she bombed my duo, and killed him because he used his dash to "too late" try to kill Shaco, so now he was a sitting duck. She kills him, kills me on the reset.
This lack of response defined that entire game. I repeatedly caught and set up people for kills the entire game. Repeatedly..... my duo and rest of team hesitated to use anything, and I think I was the only CC on our entire team, so literally.... not using It = fast base destruction, loss.
^ Happens to one team every single game, unless both teams are duos, excessively practiced, etc, and Lethal Tempo or PTA ensure that it happens.
