Large Jet - you ask why "If the likes of Ryanair, Easyjet and Go can all make money carrying passengers around Europe, we can't BA?"
Well, BA tried that. Remember Go?
A full service airline is completely different from a low cost one - it's like trying to compare apples with potatoes. BA's overhead per aircraft is something like
fifteen times that of one of the low cost boys - and it's not all just 'suits'!
As for your claims that BA's full fares are cheaper than those on the low cost carriers, I've just done an exercise here, and have compared BA's full fare economy fares LON-GLA peak flights departing 12 Sep returning 13 Sep with the unrestricted return fares of GO, BD, FR and EZY. All fares were sourced from the respective companies' websites; and are exclusive of airport fees and taxes.
Results:
BA = £280 return
BD = £177
GO = £135
FR = £99.98
EZY =£229
It's very clear therefore that BA is indeed the most expensive airline on this route - and that surprisingly EZY is not far behind it. Considerably more reasonable are BD, GO and FR.