Another thing is that the aviation businesses based there have leases which give them the right to carry on being there. IMHO the airport can't just be closed on a whim.
But 10-20 years down the road, anything could happen. A major factor in planning is the "fait accompli" principle
You are restricted by a planning restriction from developing for property. So.... you run the place down, make it an unviable business, and eventually the planning restriction will be removed because nobody wants an eyesore. OTOH everybody knows about this old trick...
GA (excluding the farm strip scene) will die out in the UK within 20 years through the lack of airfields, IMHO, unless there is a change in planning policy to enable the development of a small new airfield in the open countryside.