The motorway to Dublin has certainly benefited Dublin at the expense of SNN anyway. I'm based in Ennis and only use SNN for UK and USA flights. I could not bear the thought of commuting to European cities via LHR on a weekly basis. Several faces I recognise that used the SNN- CDG route now also drive to DUB.
For SNN and ORK to grow with more direct routes they need to attract the airlines with the 50- 80 RJ type capacity.