Aside from the reduction in based aircraft, it seems to me that there has been an even bigger problem in retaining non-based airlines.
Once Manx2 have gone, I think only Jet2 and Wizzair will be left and you'd have to worry about Jet2's future in Cork.
That leaves Cork at the mercy of Ryanair and Aer Lingus. While that's not quite as bad as the situation up in Shannon, it's still very undesirable.