The point is that BHX is playing catch-up with inferior infrastructure. The runway extension will allow airlines to operate their wide bodied aircraft with their full product, at realistic cost offering a real alternative to London and Manchester.
At the moment some of Birmingham Airports long-haul services make use of smaller aircraft, often with inferior product sold at higher prices. CO EWR and US PHL are good examples. All this stacks up against the success of new routes.
This is high comedy. Continental fly the B757 through MAN twice daily having dropped the daily B777 a few years back. It's not the case that BHX would then get a B777 if they lengthened the runway, they'd get a double daily B757 if the traffic was there. They tried this and it didn't work. To say the B757 is inferior simply because it isn't twin aisle is to misunderstand the business model. Is BHX really too grand for an AA B757 service? Would you really say no unless they brought the B777-200? Good grief. In what way is the CO B757 used at AMS, GLA, MAN, BHX, DUB, and don't miss this one, LHR, inferior?
The reason it's more expensive to fly direct from BHX rather than go through a hub elsewhere is generic. It's often way cheaper to fly over a hub than fly direct because you are paying a premium not to connect. This is a standard business model across the world and BHX is not a special case that will suddenly see cheaper non stop long haul simply becuase they put down more tarmc. That's just naive.
The reason BHX got the B757 is that this is the most appropriate aircraft for the market. I would be intrigued to know how often the AA B767 was weight restricted getting out of BHX-ORD? As in what % margin was lost. They're still in DUB after all.