I don't doubt that Jet2 could raise the funds to finance a new (as in direct from the factory) fleet, but their business model would struggle to support it, a new fleet would require far higher utilisation than what they could do with their current business model or current fleet.
Jet2's business is widely misunderstood. .com is now Holidays's bitch. The business was diversified away from scheduled low cost towards package holidays back when the credit crunch hit, specifically to avoid a futile attempt to compete with RYR. It caused some internal strife, with the adjustments to working practices (and how it was mishandled) the primary reason for the Emirates exodus back in 09/10. It's now all about the package holiday customers. A low cost version of Thomas Cook / Thomson.
Recent comms tell us some flights now have 90%+ Holidays customers on board. If a coach is waiting for customers in Cyprus, deep night flying becomes commercially viable, which the current "Queens Of The Sky" cannot manage. That's the way the business is going and it seems to scream for a new, reliable, higher utilisable fleet.
Mixed fleet flying on A320/321/330 would be far more crew efficient (let's face it, crew utilisation is pathetic, most Jet2 crew don't see the "wrong" side of 500 hours a year).
all they pay for is operating and maintenence. No need to pay for things like leasing etc.
The crux of the matter. As the fleet ages, maintenance is becoming crippling. I heard LU is soon to be scrapped due to maintenance costs going through the roof. The NEO vs the classic's fuel burn is probably enough of a cost saving alone.
You don't have to go back too far for it to have been utterly unthinkable that Jet2 would build a state of the art training centre. "But they couldn't afford it"...