Unfortunately this is the case, something needs to be done sharpish about attracting other airlines. The elephants in the room to this though as ever predictable are the Government (the DAA) and Ryanair.
What can be done if airlines were offered zero charges at Cork to open new routes I can't see it having a major affect although Ryanair would be delighted but Aer Lingus would not open a single route. Its not the Gov or Airport operator's fault to an extent they can't foce carriers to fly there unless they decide to pay them.