High fares are nothing new. I've been flying to and from SYY for over 20 years. It was regularly £100 return if you booked in advance from GLA back in the BA days. But I rember a last minute flight to INV one way was £120 this was back in 1999. Admittedly the average price is higher now but 14 years on I'd expect that. Nobody has failed anyone. It's simple supply and demand.
The best I've seen was £55 return and that was on BMI when they operated te route and we know how that route ended.
Lets not forget there is a choice on the island and that is to fly Eastern or flyBE/Loganair. However I'd put money on saying the T3 flight is a lot more expensive on average. It's certainly been more than I've been willing to pay.
I wonder if flyBE "mainline" would work with an occasional DH8 flight. Or if we'd ever see an LCC in SYY? For the purpose of this discussion I do not class flyBE operated by Loganair as an LCC.