Alternatively, Ireland could leave the european superstate and avoid economic meltdown. They only joined in the first place because Britain did so it makes sense for them to leave when Britain leaves.
The economic meltdown is more likely to be in the U.K. whilst the negotiations over article 50 continue. We don't have an EU superstate at the moment- unless you read the Express or the Mail.
Ireland was a comparatively poor country in the early 70s and needed Britain. It still does, but it has come a very long way since then. Political unity in Ireland has an appeal to many which would put aside some economic advantages or disadvantages in the short term - should the U.K. be 'punished' for leaving the EU and not be allowed a preferential deal with Ireland.
Brexit has started the ball rolling and who knows where it is going to land. I see the break up of the UK within a short time. It is unlikely that Farage will get a knighthood from the Queen whilst bragging about his part in Brexit.