Why smite ez needs to not be a thing

So I just had a game where my team completely dominated. We were doing insanely well in laning faze we shut them down our ad carry got fed and I got fed. And then the game starts to move to late game and Runeglaive ez just starts melting us even tho he wasn't fed. He had like 1 kill in the first 10 minutes. Finally our team gets beat in a teamfight where ez ults down the middle of the lane and shreds 2/3 of everybodies health and their jinx pushes down mid lane and wins the game. That shouldn't happen. A champion who doesn't get fed should not be able to carry a game.

http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/1880317061/208719826?tab=overview