That’s the airline’s concern. Imagine having a reservation at a restaurant and something happens to make the table unavailable. Should you wait for everyone els

That’s the airline’s concern. Imagine having a reservation at a restaurant and something happens to make the table unavailable. Should you wait for everyone else who made later reservations and all the walk ins who came while waiting you were waiting for your table to finish before getting seated? Your meal was already ruined, no sense in ruining the meals of everyone else? What about hotel reservations, or literally any other thing you book ahead of time. If a bus is taken out of service the people who were waiting for that stop at that time don’t go to the back of the line, they get the next bus. I’m sure airlines feel they are more sophisticated than public transit, but as a passenger I see little difference. If you look at it just from a cost perspective, then you’re absolutely right. And that’s why everything sucks. If you look at it from a human perspective and design around customer service the end result would be different.