I think it could happen before the end of this decade, but if not, it will happen eventually.
Michelle O'Niell and Mary Lou McDonald have become the acceptable faces of Sinn Fein, and not just on the island of Ireland but also in the UK and further afield.
The IRA and PIRA are no longer needed as the demographics in NI have changed. The Good Friday Agreement also changed things politically, and Brexit put a border between NI and the rest of the UK. And let's not forget that Protestants live quite peacefully in the Republic. They currently make up about 5% of the population and that would increase to about 8% with unification - they really do not have anything to worry about.
Unionists are a different matter. They are as much a political as a religious problem. Something will have to be done to neutralise the UVF and UDA before they cause trouble. Ireland has seen enough troubles.