My personal pet theory is contractual obligations and/or high-value customer placation. There are certain high-frequency business travelers that need(ed) to tra

My personal pet theory is contractual obligations and/or high-value customer placation. There are certain high-frequency business travelers that need(ed) to travel on whatever date and time they pleased, and just cutting one's flight network entirely meant losing them as a customer and potentially paying some fines. However, actually running that many flights is extremely uneconomical. So instead they basically cancel whatever flights don't have one of these particular business travelers on it to try and move demand around. Of course, those high-value fliers have reduced their use of air travel in the same way everyone else has, so a lot of flights are basically "virtual" and will never actually fly unless they meet some particular threshold of value to the airline. If that's the actual case, then what airlines should be looking into is bringing back standby ticketing.