The sooner the sharks and incompetents are run out of GA, the better for us all.
Very true but I doubt it's going to happen any time soon.
I can think of just two ways to make it happen:
A properly managed and funded school sets up at the same location, with new modern planes etc and, after a few years, the other one(s) go bust. The problem with this is that the "others" will always undercut the new one, because one can run old planes a long way into the ground before they can't be used anymore.
The airfield takes an active interest in the management of flying schools based there, allowing no more than one to set up, and vetting their finances (and whether the Directors have a "record" at the Companies House, CCJs, etc) beforehand. Rather than just gratefully accepting the rent from anybody, as most airfields seem to do.