I disagree. DSA has a strong catchment, but like STN, it will take time to develop services and establish its base. It is not the size of the catchment that determines the fares, it's the competition from other airlines, and like I said above, some competition is good and the nature of open skies, but the problem with too much competition is ultimately someone has to lose - this was shown with Monarch last year and there may well be further consolidation to come.
DSA is not in the same league as BLK or MME, and in terms of catchment areas with the phase II link road about to open, i'd say DSA probably has a bigger catchment area than leeds ... and with the Sheffield city region really starting to propser, there are good things ahead for the airport I am sure.