I think in particular what you are seeing with the irish boys, is they are trying to get into new territories eg pubs with little/no craft, and expand into craft pubs.
Its a little bit like chicken and egg, the brewers want to sell what they brew, get known, and can then create outside a core range.
Like i said, WJ Kavanaghs are pouring Bru Dubh regularly, and as far as I know have taken out O'haras stout. The Westgate in Kells which is another Bru supporter is regularly pouring and the feedback i've heard is a lot of lads who were Guinness drinkers have moved across.