Centre,
You are essentially correct. However, in the comparatively recent past, MAN and to a lesser extent BHX have been to all intents and purposes the only option for pax from almost everywhere outside of London.
But since the advent of Locos, many people appear to be sidetracked over just the low cost option. What it has actually done is open up markets so that people can travel from their own local airport without the need to travel long distances to an airport. For example, if you live in MAN you would rather fly from there than say LGW. But the same is true if you live in Leeds you would rather fly from there than travel to MAN. Its a natural reaction, although cost also plays a part in that element. Hence it was fairly obvious that airports such as MAN and BHX would take a bigger hit. Its extremely unlikely that they will regain such a dominant position in the short haul market again.
After stating that, there are other opportunities in direct Long haul flights, where there is less competition and people are more willing to travel further to the airports, although there is more competition now from airports offering interlining outside of London. I am not sure yet how the long haul locos such as Air Asia may affect the market or if they are almost unique or at the beginning of something major, although the loss of Air Comet does not bode well in these areas. Ryanair is also an unknown quantity in the future for long haul.
Therefore in conclusion, I feel that growth will return to the previous highs, but perhaps more slowly and in different markets. Of course it is not helped by the Government/Green brigade seeing aviation as a milch cow to wring every penny out of travellers with higher taxes. (If the Government/green brigade REALLY wanted to cut co2 emissions, the 2 easiest and cost effective ways is to reduce the speed limit to 55mph and stop using water in plastic containers, but thats not sexy and theres no money in it for the Government (In fact they would lose millions)), but it is very green. Aircraft emissions are puny in comparison.
When Man does recover to previous highs, there will be more pressure on slots etc, and if the same models are in existence then, then I feel that Man (and LGW) would slowly ease out locos to concentrate on what they see as their core markets, ie premium and long haul, perhaps backed up with I.T. although again I'm not sure how much longer that market will hold up in its current form. Locos would be restricted to off-peak.
Just my thoughts.