I am not quite sure what website you are looking at but if you look at flights in August the minimum one way fare is £57 with most around £95-£120 and some up to £134 one way.
I agree that we are in a transition period and this makes it all the more important to ensure the routes have a 'helping hand'. I therefore do not agree re Heathrow or London City as an option take a look at what is going on in Teeside. There the Mayor is subsiding a London Heathrow service they now have three flights a day with Loganair because they recognise the strategic importance to the area and the potential investment the route brings. They are not even an island and have train options and yet they seem to get it!