It's a problem with MOBAs in general. MOBAs lack an "okay, you're turn" like all other sports.
American football? You score, other team gets a shot. Football? The ball is changing teams so often it's a back and forth. Hockey, basketball, and so on.
If someone scores a goal in football the scorer doesn't suddenly get 10% stronger kicks or 10% more accurate shots. The reward for getting a goal is a goal. In MOBAs, the reward for a kill is time to push objectives, time to farm, AND gold on top of that. Of course, comparing the two 1:1 isn't fair either, but those sports do allow comebacks much more easily.
The system itself is incredibly snowbally. It's just the way it is. You can mitigate it all you want with increased global gold, decreasing champion kill gold, and so on, but it will forever be snowbally until the point where a kill gives no gold. Not that I want that, necessarily.