Fares inn DUB-LON can be eye watering. EasyJet would be a turn-up for the books and watched carefully by the likes of Wizz. Norwegain are the only European LCC who have managed not to be hounded out of DUB by Ryanair’s preditotry, anti-competitive behaviour. Both Ryanair and Aer Lingus are weak in Scandanavia, which helps Norwegian.
Im not sue Ryanair or Aer Lingus would take kindly to the easyJet invasion. Aer Lingus have access to the IAG slot pool, Ryanair’s Belfast slots were a competition remedy also? So they may struggle to add significant additional frequency. They might sell every seat on every fligh for €9.99 though.