Why are you guys so obsessed with price vs. distance? It has never worked like this in the airline industry. With that logic, flights like BEB-SYY should only cost pocket money because you can fly TATL return for 400 quid or so which is like 40 times the distance than BEB-SYY. Even if you get into a cab, you have an initial fare and only on top of that the meter kicks in, making short rides disporportionately expensive.
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.
Just out of curiosity and from a distance - what is Eastern's selling point as they have been soldiering on for a couple of years? Do they hold a contract by the NHS or someone else?