Genghis, I suspect that if planning permission for housing development on the Woodford airfield site had not been forthcoming, and the local authority had insisted on no change of use from being an airfield, what you suggest would have happened.
I suspect (I really don't know) that this is how the likes of Biggin don't become housing estates.
It would not be financially viable for any aviation interest to outbid housing developers, buy somewhere like Woodford, and operate it as a GA facility. Land in even a semi urban environment will always be worth many, many times more as a housing development site than as home to an aviation business if it has planning permission for housing.