This site is owned and operated, like several Irish heritage outfits, by a sole private owner. The Achilles' heel of such operations, without an actual preservation society set up, is that when the owner becomes elderly or infirm, the whole thing often folds up.
I have not been in touch with the owners for a while, so I am not in a position to comment on whether this is the situation with them, but what I do know is that Jackie and his good lady are indeed elderly, and other than that there's just their son involved; plus, they have not been trading frequently in recent years, which could suggest that those involved don't have the time.
It's a pity, but it is reflective of the overall low level of interest on this island in railway heritage. As you say, let us hope they are in good health.