I think they have Peacock. Shannon has taken an absolute pummeling in the last year but they will be better off for it in the long run with Ryanair competing on a level playing field to everyone else. Ryanair are still there of course so there are obviously some routes worth sticking around and paying higher fees for. If they can't make the marginal routes work there are other airlines with smaller sized fleet that can give them a go (e.g. RE/EIR).
If the demand simply isn't there to make a particular route profitable, there's no point giving it to Ryanair on the cheap just to boost pax numbers at the expense of every other airline.