Combine the fare changes with changes in seating in aircraft described in this article:

https://simpleflying.com/delta-air-l...-debut-london/

What do you have? The airlines have finally figured out a way out of the mess that deregulation has caused them.

Filling a plane with cheap fares and "Greyhound passengers" is an economic model that does not work and drives airlines into bankruptcy more commonly than into profit.

So what to do? Bring back the "coat and tie" passengers of the 1960's who paid the amount that it took to successfully run your airline, with the added benefit that they are less likely to be disruptive to your operations staff (looking at you Spirit/Frontier passengers).

It will be interesting to see if it works but with both United and Delta doing this, both with presumably mountains of data to support this move, I would not bet against it.