It simply won't happen. The Irish Government won't allow it nor will the EU as the lack of competition in such a market wouldn't be in the consumers interests. Having said that when SAS acquired Braathens when faced with the alternative of closure they ok'd it but then we saw the rise of Norwegian to balance things out again.
The problem with Ryanair is that whilst they are the first to complain about dirty tricks I think you would see an interesting approach when directly competing with a new entrant.
Notice how their booking system is back to its old nasty and illegal habit of showing prices excluding taxes and charges at the first screen. The message " select a flight " appears.......naughy Michael. been like this fopr over a week now.....won't be long before the OFT are back on to you......hope they fine you this time...