You had a very nice idea tho I don't think any project wants to do that unless there is strong pressure from everyone, not just bounty hunters alone. Why paying a fee to conduct bounty aka escrow as long as no one can force them to do that?
Yes, creating a bounty and escrow is something that you don't have to force if the project doesn't need it, but if that is done then there will be a good effect for the project itself, because on a real foundation they will be really strong in the future. if the project can be successful in a timely manner.
Some of the legit projects already have similar things like that. They hold bounty with a high reputation bounty manager and pay all the fees, funds to him just like it was in escrow. In the end, it's really up to each project if they want to do a serious business or not.