Unionist political entrepreuneurs shot themselves massively in the foot backing Brexit and being hardline on regulatory alignment with Great Britain, all because of some warped imperialist-era superiority complex. They cornered themselves into not only precipitating a massive constitutional crisis but also the eventual selling out of Unionism by an English nationalist movement, and the creation of an all-Ireland economy in the works, which will make Ulster far more interdependent with the EU economy.
That said, we shouldn't underestimate the 10-15% of Catholics who are soft Unionists and would rather keep some form of the goodie bag they get from Westminster : the NHS, some form of stability through the GFA, education, a currency that, once the Brexit process is finished, will likely stabilise. And it could take another generation for some of the more Unionists to ever accept peacefully a transition.
Without hyperbole, I don't think Brexit will ever 'finish'. It's slowly become a euphemistic catchall for 'relations with the EU', as well as an index for tribal cultural politics in England. Whatever impact it has on NI, it certainly won't be one that brings stability.
It's worth repeating just how screwed the Unionists are in NI right now. Returning to the status quo ante Brexit is impossible. Suppression of growing nationalist sentiment, nevermind strengthening unionist ties with the UK, is a non-starter and all but mandated to become harder as the Withdrawal Agreement comes into full effect. Any cooperation with ideological conservative allies in England is a dubious prospect - they did just sell them down the river out of convenience, after all.
It's not just a question of Unionists having no good moves. There are no moves to make whatsoever. The WA mandated plebiscite on continued economic alignment with the EU scheduled for 2024 (a near certainty to pass), will probably be interpreted as a proxy border poll regardless of what politicians on both sides of the Irish Sea (and the border) insist. As it becomes clearer how distant and diminishing Westminster's prerogatives and powers are in the day-to-day lives of those in NI, the inexorable logic of reunification will become harder to resist.
