Patch 8.10
Currently, the rewards a player gets for performing well are too split amongst the whole team, and we'll be looking to remedy that over time. We're starting this patch with Bounties, shifting the reward from a team one to a personal one, and we'll be investigating other team rewards going forward
[Removes 1 Kill Bounty]
[Removes 2 Kill Bounty]
[Converts all other bounties to killer only rewards]
[Death sets bounty back to 0 instead of -3 bounty]
Patch 8.13
A bounty is a reward to a team who takes down a champion who has been pulling ahead. Essentially, it's the way we make it worthwhile to keep fighting even while you're down. Currently, those bounties often don't kick in until it's too late for the laning phase: Fighting from three kills down is pretty terrifying. We're introducing a level 2 bounty—and also increasing bounty gold overall—to make fighting from behind feel more rewarding. Still the same risk (dying again), but a much better reward.
[Re-adds 2 Kill Bounty]
[Reverts solo gold reward back into team gold reward]
As far as I can see, none of that was to reduce the total gold in the game. It looks like 8.10 was intended to reward individuals who took down high priority targets, while 8.13 is intended to but some breaks on snowballing.