They won't until political winds shift and you get some regulatory intervention. I would project around 2030, when the major carriers are all ground away and the financial shenanigans of low cost airlines (example: Norwegian Airlines with NY->Europe trips that cost less than the parking) run out of gas.

Without that, there's no motivation to do anything but shave every marginal dollar. Competitive forces are limited and will get more so over time. My uncle drives freight trains for living, and they pay extra to remove seat cushions on the locomotives because they don't want to spend opex on replacing torn cushions down the road.