I'm inclined to agree with Copenhagen, it's about commerciality. Perhaps EI had every intention of going year round, but prevailing bookings may have just not added up. The distances involved in the lower winter after the Christmas rush are just too lean, may be better to keep the metal on the ground.
Shannon are in bed with Ryanair, almost everything will be on Ryanair's terms, and that will continue until the screw is turned when the airport management aim to make a sustains be return. In which case FR will make curtailments.
All the better for Cork airport, who hopefully will be wise enough to avoid designing deals to get FR to operate the lions share of flights into Cork ... A much more sustainable future will result ...