Anglican vs. Catholic cultures determine elections, who serves, works in government, who gets contracts.
There is no US Constitution type of governing law there.
Although the Church is in decline at the moment in both religions in Ireland, history shows a historical wax and wane, flow and ebb, to and from the Church. In other words, it’s a near certainty that future generations will flock back to their faiths reinforcing the historical divisions. The way that peace has been achieved is to respect the divisions administratively.
I’m not so sure.
Catholicism in Ireland, what with Maynooth and the love affair that the Irish have with islam together with their gay PM and rush to embrace abortion and everything else probably forever kills Catholicism in Ireland.
Catholicism in Northern Ireland, while somewhat a separate animal, will likely be pulled down by these same forces.
As for historic Protestantism in Northern Ireland, I think demographics and history make the decline irreversible. A deep and historic Protestantism (meaning vitally connected to historic Protestantism) is basically gone from the rest of the world...but in Northern Ireland it lasted longer than most places. For all of his faults, Ian Paisley was a genuine, recognizable and authentic historic Protestant. (I’m not saying anything else good or bad about him....I’m only noting that he truly channeled the spirit of Protestantism [at least one spirit, a historic strand], in a living historic sense...and obviously the conflict that surrounded him helped him forge that identity).
NOW....what could happen?
Something like a South American non-Catholic but hardly historically Protestant revival could occur in Northern Ireland.
But I don’t see that sort of reupping the historic Catholic or Protestant cultures that were once so identifiable over the entire island.
All that said....we are both simply trying to predict the future lol.
And the future is always filled with surprises. So I submit the above humbly and non-dogmatically...just for food for thought. :)