Why is an order of new aircraft rubbish? Why does everyone assume that if jet2 ordered new Airbuses that the 737s would be disposed of? Why does everyone assume a Boeing order would mean Max and not NG? Why does everyone consider the mail a large part of the business?.
Jet2 has evolved and is now being heavily influenced by the holidays division, this is still relatively new and still growing. It may be that one aircraft type is not a good fit for this business (TCX and TOM don't use a single type).
The fact of the matter is Jet2 probably wouldn't be in the position it is today without using pre owned airframes. What is missed is the resource jet2 are putting into looking after these aircraft is considerable. Capital for new airlines is not easy to gain and lease costs for a new or small airline are huge.
I do not know the answers to all of the above questions but an open mind is required not constant droning about how everything is rubbish.