Picture this......
The report on Plymouth tells us what everyone already new that unless the airport gets a decent runway extension it will become commercially unviable. As Exeter grows all the traffic would migrate there. If PLH did close what would this do to Air Southwest NQY-PLH-LGW service? If NQY-LGW did not stand on its own perhaps it would then have go NQY-EXT-LGW or NQY-BRS-LGW?
What if a NEW challenger started a real low cost service to London from NQY, either direct or via EXT and took on Ryanair ( hardly a major route for them) and Air Southwest ( backbone route and even BA made a profit on it) then suddenly the whole picture changes.
Since this is the Exeter thread the only thing is for sure it will continue to grow and thrive and is logically the airport for the South West and for now anyway Flybe is (probably) the airline.