Your argument is that the airlines had a prescient view that their revenues would decline relative to their competitors, and before that happened implemented ba

Your argument is that the airlines had a prescient view that their revenues would decline relative to their competitors, and before that happened implemented baggage fees to partially offset that fall. With natural experiments like this it's painful to disentangle cause and effect, but with the timing (fees, followed by revenue declines) I'm inclined to see the author's explanation of fees being a more likely cause.