With massive bounties, why don't they fully reset when claimed?

When bounties were smaller, it might have made sense to not fully reset a bounty after one death, as the extra gold didn't make a huge dent in the lead.

Now though, you have a champion getting a 900g bounty at 6/0, the 900g is claimed which is like 3 kills back, and the guy still has like a 600+g bounty?

I think it's pretty silly that you can win teamfights mid game 4 kills to 2, and yet the enemy team gets twice as much gold off the fight and your bounties remain higher. They're literally making a comeback by losing fights if your allies are too low to take objectives afterwards?