Not sure it is that simple and I don't think you can blame the GA owner/operators for this.
If a city-based airport starts hiking its charges to GA it is usually because they are deliberately trying to get rid of them. They want the high volume passenger traffic and the opportunity to fleece them at the airport shops and car parks.
As a GA owner operator what do I do, knowing that the airport operators will keep tightening the screws year on year until the last Jodel is off the airfield.
I do what most of us do, look to see what we can afford in our own budget and find somewhere suitable.
Then we find a downturn happens and passenger traffic falls. Airports like Plymouth or Filton shut as they are worth infinitely more as brownfield development sites than as an airport. GA can't bring in anything near enough to cover the costs.
It is left to a few visionary airfield operators (I have a few in mind) who keep the faith when they could easily take the money and run.