That is the beauty of statistics. They go with damn lies! There are a few ways of measuring wealth and you have used one set. You take my point though Yorkshire and its region should not really be doing one seventh of MANs passengers on a level playing field should it? Then you add in the considerable NE, north midlands and Lincs passengers that would use a centrally positioned northerly airport.
Yes MAN will always be the main airport for the North now as no one will pay for a better placed airport between the conurbations.
It is down to strategy of running an airport such as when MAN didn't want loco operators and allowed LPL to rocket up to you from virtually zero. LBA has never been given a chance to show what it can do. If LBA can be invested in and surface access bettered to allow a critical mass of passengers to pass through it between 5 and 6 million then there would be a period of equalisation so that a Yorkshire airport would a be moving a more realistic 25-30% of the norths travelling passengers. There will be no long haul from LBA in its present position - the margins are too tight.