B2B, CO's complaint is that they make no money on the route because of APD, especially as pax can use DUB where they pay next to nothing.
Locos are known for reducing every possible cost, but
afaik, no loco has ever managed to negotiate a better tax rate with HMRC! Also, much of the loco advantage over trad carriers is gained by negotiating better airport handling fees - and this is much less important on transatlantic sectors where fuel is the biggest variable cost. Again, Jet2 haven't got any kind of less thirsty beast here either - I would guess CO's 757s drink a little less as they have winglets &
afaik, LS's don't. So considering that CO offer 50+ onward connections from EWR, and that LS have virtually zero experience in the (scheduled) transatlantic market, why would they want to replace CO?
And finally, can I thank whoever started this thread for calling Jet2 what they are - an airline, NOT a website. I really hate it when everyone else calls them Jet2.com - the prime service they offer is flights, not flight comparison!