Doesn't matter what anyone says, the Army always manage to cock up an airfield when they move in. Look at Abingdon; a fence built all round inside the peri track; Catterick, houses built on the edge of the runway.
What ARE you talking about?
The RAF decides it no longer requires an airfield. The permanent camp and sheds could be used by an Army unit. A unit is identified and posted in. The airfield, remember, is no longer required by the RAF. In some cases, the Army makes use of the land, in others, it is simply fenced off.
Or are you suggesting that the MOD expend resources on maintaining runways, ATC and fire coverage for airfields that the RAF no longer require?
If a former RAF station were to be returned to flying status, in most cases, there would need to be a complete rebuild irrespective of current use. They have been out of flying use for decades. Examples:
Leconfield
Abingdon
Thorney Island
Waterbeach
Oakington
Swanton Morley
Some never had paved runways in the first place:
Grantham
South Cerney
Then there are those that DO retain the airfield, for RAF use:
Topcliffe
Dishforth
I would also remind you that the RAF is not immune to trashing its own former airfields. Where is the SLAM at RAF Honington? Next to the runway.
Then of course there are those that just get paid off to rack and ruin:
Hemswell
Watton
West Raynham
West Malling
Manby
Would you rather that the first group went the way of the last?