Is not MAN living off the back of the capacity constraints at LHR?
Which airlines have explicitly said that as they can't expand LHR ops, they are "forced" to use MAN? Can MAN get Cathay Pacific back with the known large demand - no, they'll find ways to get a 4th LHR daily service up and running before satisfying the seemingly obvious choice of MAN to help relieve the constraints of limited frequency restricting passenger mumber .
There's been a few airlines who have stated that they are going to LGW as they can't expand LHR schedules. Some of those would be ones that MAN would like. We have some airlines stating that they are unable to serve Britain due to lack of access to LHR but it's the myopic view that London is everything in the UK that needs to be eradicated.
Do passengers want to go to MAN at all? Or do they really want to go to Birmingham, Gloucester and Leeds, but find LHR too tiresome and the train connections so poor (you have to go via London and a separate tube journey).
That's quite right. No airline in the right mind would want to go to a regional airport as there isn't the demand. So when EK surprise everyone by getting an A380 to MAN a bit ahead of schedule by suggesting enormous untapped demand and that customer feedback indicated that they would be able to sell F class then we have to accept this as uninformed airline logic? That there's a solid amount of premium demand collectively carried by around a dozen other airlines would suggest demand is there unless all those airlines are equally uninformed about passenger demand like EK?
If you want to go to Birmingham or Gloucester then you would not want to use MAN; AA's problem when they were serving BHX is that the premium passengers were using LHR. From the West Midlands southwards you will find only a small portion using MAN. Look at CO who stopped serving Bristol. There's a route that southwest England had to service America but it didn't last. That premium passengers perferred using LHR should tell you that there was barely any flow of passengers northwards and the idea that the displaced BRS aircraft miraculously helped to add frequency at LHR for them reinforces that view.
As for Leeds, yes there's a lot of passengers coming from the "wrong" side of the Pennines to use MAN, but there's more passengers outside southeast England using LHR - do all those passengers want to go to LHR (or Boris Island)? I doubt it. The view that MAN is only allowed to have passengers going through its terminals whose journey ends or begins in Greater Manchester and is not able to have passengers from adjacent metropolitan areas is, frankly, laughable.