Sorry DJ6 but still on message: if you're asking can many of the regional airports not benefitting from the loco flights survive when less than half of their revenues come from landing fees, IMHO surely not; the cost of conforming, insuring, employing etc for few aircraft that pay a decent landing fee can't make financial sense. Just look at the cost of RFF and ATC.
And there's a limit to how many breakers yards are needed. Redundant municipal airports on brown field sites must be prime developmental land, and councils looking to cut the cost of their local airport will surely be attracted by development potential. After all they want jobs and prosperity for their community, and if the planes have stopped coming in, bringing in investment, why fund it further?
Yes, smart private airport owners will already have seen local potential, but i doubt we can extract a credible national business model for under-utilised regional airports.