A 50-litre (88 pint) keg of good beer costs about €160 wholesale, with stout being a bit less. That's €1.82 a pint. Publican sells it for €4.06+VAT retail (i.e. €5), leaving them with a gross margin of €2.24.
Out of that there could be a load of things to be paid, including high rent and high rates. Then again they might not be high. If the question you're really asking is "is there price gouging going on" then answer is it depends. In some cases yes, no in others. Only a proper consumer organisation could answer that in general terms... where have that new crowd gone?