I don't really believe the most hardened loyalists will keep fighting once the British government is gone, and reunification with the Republic, or assimilation into the EU (whichever comes first) occurs. They will be so marginalized, as to be wholly ineffective.

As you say, Jimmy C, most Ulster Protestants will not identify themselves as anything but British, even after hundreds of years and many generations of their ancestors living in Ireland. As someone else said, British loyalists and unionists, once they emigrate to the US or Canada, identify themselves as having been Irish. But that is because the tide has turned in NA. Despite the fact that the Anglo American institutions of Canada and the US still retain their power, the perception of Anglocentric culture is often quite negative, whereas Irish culture is more often seen as positive.

It wasn't like that in North America 30+ years ago, when the Troubles began. Then, the perceptions were reversed.

But to be fair, many Ulster Protestants nowadays would just as soon not be associated with either the Church of Ireland or the Orange Order, in the same ways that many Irish Catholics don't want to be associated with their church. The reasons behind that have nothing to do with the Troubles, really, and everything to do with the decline in membership and lifestyle habits which no longer put religion at the center of social life. In that sense, Ireland, north and south, is just like any other modern Western country.

It also discounts the "religious conflict" theory to a large extent.