Ehh well the current system of giving you money WITHOUT any service level guarantee doesn't seem to work well either as DFS was stopping/slowing recruitment to maximize profit while at the same time they are doing all kind of non core stuff like running towers in other countries.....
So actually paying according to service levels does definitely get managements attention!
Indeed , but what they do with less money ? Which business do you know where if you pay less you will get better service tomorrow? In a normal world, if you do like the product or the service, you avoid coming back or go to the next shop selling similar product(s) or providing similar service.
Problem with ATC is that there is no real alternative. One airspace one provider, You can change the name on the building or the Tower but it is almost always the same system and the same people confronted with the same issues..
Constantly asking for reduction in costs is race to the bottom , ATC or airline..
Everyone would like a better more modern ATC system and more staff to run the thing when demand is there. But in many places we keep the old stuff and plan for the average traffic, not the peaks, so you get more and more delays as the traffic raise year after year.
Summer 2019 will be a mess in Europe. Investing more and recruiting more controllers will help ( in a few years) but paying less those in difficulty will ensure that you will get a bad service for decades to come.
Finally ATC is not "generating" delays , but keeping the capacity it has at a given moment within safe margins. Not only traffic but weather /CBs or equipment failures also restrict capacity . Building more capacity/ redundancy for those cost a lot of money too. .