Dooby,
"Upcountry routes"?
First there is the fuel issue, in Brymon days, once they'd started the BRS route, they'd tech (fuel) stop en-route in NQY, additional operating costs, landing/handling fees etc, I guess Skybus similarly tech stop in LEQ.
To fill 50 seats, except on a minority basis, it would need to multi and multi sector ... perhaps BHX/BRS/EXT/NQY/ISC and return ..... would this be an improvement upon a Twotter operating, moreso, direct services?
This is the quaint and beautiful Scillies we are talking about, it's not a 50 seater destination, there aren't 50 ISC punters getting off each train that arrives in Penzance nor Newquay nor Exeter etc. etc. etc.