I don’t think ORK-DUB will ever come back. The connections by road are dramatically improved and the busses are frequent, affordable and more environmentally friendly. If EI really wanted to they could codeshare with a bus operator for onward connections. AF, KL and LH do this with train operators on the continent, there might be more.
A US route would be great, you’d imagine there should be good incentives for new routes and with onward connections at the US end the route should be viable. Little interest has been shown so far though.