Airports with terminal facilities and some history of passenger flights (BLK, CWL, MME, CBG, CVT, DSA) are most likely to struggle because they are looking towards the diversification to allow them to pay for the facilities for additional passenger flights. Some people expect the revenue from training, scrappage, storage or whatever to be allowed to cross-subsidize passenger operations.
Most of these airports had their best years in the loco boom between around 2004 and 2008, when the Blair-Brown debt-fuelled binge was at its height. At that time, airlines were searching around to be the 'based' loco somewhere - anywhere! So Thomsonfly found itself at BOH, DSA and CVT, EUjet at Manston and BMIbaby at MME and CWL - they were the last entrants and got the dross. No surprise they've all effectively disappeared.
Kemble has been successful despite never having hosted airline operations because it's run privately as essentially an aviation-property business. Lots of aircraft stored for long periods; land leased for parting-out; hangars used for distribution, engineering training and more; even new hangars built for light aircraft!
These marginal airports are big chunks of property with runways attached. The more sophisticated the type of use made of the runway, the more expensive the ancillary services such as ATC, nav aids etc; to say nothing of the costs of keeping passenger handling services ticking over.
CVT seems to be making progress having lowered its sights, DSA's and Teesside's owners are struggling with the concept, despite being a property company. CWL has St Athan on its doorstep, and the coastal airports (CWL, BLK, NQY, MME, PIK, Manston, BOH) are going to struggle to find distribution businesses to locate there.
I'm sure all could be used as housing, but whether there is enough aviation-related 'diversification' available is open to question.