So, diversification of their business model is seen as 'desperation'?
Utter, utter nonsense.
They are no more in trouble than any other airline at present.
It's a wise move and a safer plan than the inept cycle of constant prodding of unpredictable scheduled destinations that the loco operators seem to be forever trapped in. Jet2 are actually looking ahead here, rather than backtracking and clutching at straws. It makes perfect sense. If they had a 'stick to our guns' business model that wasn't willing or even able to adapt, then they'd be stupid and naive. Fact is, they're moving and shaking. It's a good thing.
Find new routes, axe old routes, find more new routes, axe more old routes, axe some of the new routes, re-instate axed routes, etc... this generic loco cycle has been going on for long enough. It's time it evolved. The market is changing. Jet2 feel that the 'do some loco, do some charter' thing might work for them. To at least try it makes perfect sense to me. To not try it would be far, far less progressive.
On a side note, I find the football fan-like allegiance by some forum members to airlines and airports and their business models very confusing. If Jet2 are gone tomorrow or still here in 10 years time, it makes no difference to me. But looking at them with objective eyes and having a lot of experience in this area of the industry, I don't see how anyone can say yet that what they're doing is a bad thing. It would become a bad thing if they tried it and it didn't work, but they still persisted with it.