I disagree that airlines "discovered" that price was the only concern. Yes there were customers who were only price driven, but there are also many who aren't. The problem was that airlines only competed with frivolous, easy to implement improvements, few of which had any real impact on the customer. The real high impact services are seat comfort, entertainment, and airport experience. But airlines focused on the few high revenue customers, and let the product for the large portion of passengers drop to a commodity experience.

That's why I pointed out the rail travel alternative. Airlines easily fell into the trap of offering the same product as everyone else with no difference in the meaningful aspects. If they have to compete against something that offers a better, or at least different, product, then they have no choice but to start looking at their economy product.