Sadly this has been a result of bad government policy that for the past 10 years has been very US centric when we should have been doing some serious relationship building with China, India, Pakistan, Brazil and Russia as well.
It's actually worse than that.
One of the factors in keeping the DUB runway short was pressure from the SNN lobby. An artificially short DUB runway meant that there was one less reason to remove the SNN stop over; flights from DUB
had to land at SNN if they were going to make it to the US.
With the arrival of the A330's in EI that became less of an issue, but the runway was still a limiting factor.
AFAIK, Dublin has the shortest main runway of any main airport in any European capital.
Just one example of how "Parish Pump Politics" hamstrings national issues in Ireland.
JAS