I wouldn't mean it as a blanket statement as such, junctionmad. BR (or whatever it may BR collectively be referred to now) is a sum of many very diverse parts. Many of these parts simply don't exist in Ireland, didn't, can't and won't, for example very long distances, heavy freight traffic out of mines like bulk coal, and so on.
Thus, of necessity Ireland's railways have a smaller area, smaller market and smaller number of potential niche markets to follow. Of those that do exist, and in the circumstances likely to prevail, actual subsidy-free commercial viability is unlikely to be possible in any sense.
Again, if we subsidise a private operator, we're subsidising the operation of the railway plus fat cats and shareholders.
One thing is very true though - your comment about incentivisation. Remedies for this type of thing come very slow in Ireland, especially in nationalised entities (the ESB and HSE are WAY worse than the railway) - but can be found without actual privatisation.