It appears EUJet learned nothing from Aer Arran's experience a few years back - they may as well just have changed the heading in the Aer Arran's press release explaining why they pulled out of Dublin - Shannon.
Lingus will stay there for as long as they need to comply with the Shannon stopover as it costs them nothing to carry domestic passengers - why should they step aside and turn away business. Having them clearly blocking the development of regional services to Dublin helps (albeit in a small way) the case for ending the stopover rules.
Personally, I'm amazed EUJet threw in the towel so early - total extreme from Jetmagic's approach to poor routes so can't be a bad strategy!