As long as the protestants keep using birth control at rates higher than Catholics, the trend will continue and Catholics will be a majority by 2050. As it stands right now, the Brits are trying to figure out a way to get out of Ireland without too much violence.
You wrote:
“As it stands right now, the Brits are trying to figure out a way to get out of Ireland without too much violence.”
I don’t think they’re trying to figure a way out. And I don’t thik they’re all that worried about violence either. There was very little violence against Protestants in the south when the Brits left there. Even today the Protestants in the south control many of the financial institutions, industries, etc. If there is violence in the north, it will be because the Catholics have been poorly treated for centuries (with Bloody Sunday an example of such treatment).
Yes, driving the protestants out of Ireland helps as well. Tens of thousands fled the violence.
If you think higher rates of "birth control" explains how the Protestant population of vast tracts of Ireland declined from 30%, to 0-5%, in the decades after the Republic was established, I've some exciting investment opportunities for you.