How many more years do you think the company will operate if they continue to make a financial loss? When you've cut as many costs as you possibly can and are unable to increase revenue by increasing pricing then where do you go?
Unlike other airlines, GB's future is not its own. It is constrained by the BA franchise and what KH would like to do as part of his profit improvement plan is not in-line with what BA will allow.
As another poster has already stated, is it all not so "inevitable"?