Unification will happen when the advantage of receiving such money will be clearly be offset by the disadvantage of having a broken political system (NI regional government is boycotted by unionists, while the national government is boycotted by republicans). As money reduces further and further while annoyances get bigger and bigger (because of an entrenched "England-first" government pursuing policies like Brexit), that threshold gets closer and closer.

Those subsidies don't seem to be enough to save it when the infrastructure is crumbling and everyone is moving abroad for jobs.

>money they likely wouldn't get from Dublin

They would get it from the EU then, and probably a lot more, as the UK gov is now struggling financially to stay solvent. The EU can very generous if you can play the game right. Just look at Poland 20 years ago and Poland today, the difference EU funds and the EU open market made, is night and day. It has also benefiter the Republic of Ireland. I doubt they would have been in the same state today without EU membership. For all its faults, the EU has been a force for good many times. Another English speaking region joining the EU could be a mutual benefit.

It used to be the case that the roads would get noticeably worse as you crossed the border into the republic, now the situation is reversed.

NI receives a disproportionately large amount of money from the UK gov compared to other UK nations.

The place needs to be actively developed, not repeatedly patched up and sent on its way to hobble along.

NI is a little better-off than much of England in that regard, outside of Tory towns and villages. My home town never recovered after Thatcher.