Peel ran all three airports through a central team. All of the important stuff relating to airline negotation, route development and so forth was done by the same team that covered Doncaster and Liverpool (combined passenger numbers of 6.3m). The local airport directors were there to co-ordinate the front of house, the agencies and in general to keep the place running on a day to day basis. Blaming these guys for route development issues is utter rubbish, so find another scapegoat if you need someone to blame
Maybe start with the people of the North East and ask them why they didn't use the services in sufficient numbers when bmi baby, Globespan, Wizz, Ryanair and Thomsonfly were all persuaded by Peel to offer services from DTV.