Could that be because the economy in general, and the flying market in particular, promptly lost those profits and went into DEEP multi billion dollar per year losses industry wide for years? If that's what you're pointing out then that would be technically correct but incredibly obfuscating as its radically out of context within the same historical lens you're trying to view it through.

If our 5+B/yr profits dry up to not only zero, but multi Billion dollar per year losses year after year, then I'm sure any gains we're asking for would, in that hypothetical case, be "unreasonable". But that's not relevant and everyone knows it. Obviously if that were to happen, they would come for concessions and any mediator or arbitrator would not be on our side.

Had the events of 9-11, as well as the coincident recession that was starting anyway not happened, and they kept making say even a measly 1B/yr in profits all those years instead of hemorrhaging Billions per year, they could have "afforded" those rates. Very easily. The rates weren't even a rounding error amidst the flurry of back to back to back multi Billion dollar blunders made by management that have been well documented:

Buy high/sell low fuel hedges, buying 2 regionals for 2B each and writing one to zero and selling the other for 300M for rediculous terms to another regional, the poorly thought out Taj Mullin in Bos that gifted historical capacity to a ruthless cut throat competitor, smash and grab "retention bonuses", going all in on nearly a thousand RJ's thinking the backbone of the domestic network was flying the world 50 high cost seats at a time, and many, many others).

So what was the relevance in saying "they did not afford them for long" when that is contextually irrelevant?