Easy for bad players

With the midseason update out and many items having been changed, the game seems to be easy for bad players to get ahead just because they are abusing the items.
For example, after playing a game as ezreal against a tristana, I was ahead in cs by 50 after 15 minutes but after she got 1 item she was able to 1v2 our midlaner and myself while misusing her ult.
In a sepereate game, I played against a Quinn top and after getting static shiv and dusk blade she was able to e onto someone and deal half their health. It just seems unfair that players who are unable to even farm well can just wait out and even while behind in items win because they are abusing the item changes.