Originally Posted by
AlastairGordon
When you think about it, why would an airline want to favor someone who flies 25 times in a year, spending $200 per ticket, over someone who flies once on a $5000 ticket?
Consider the route network as an ecosystem. If an airline doesn't fill the domestic flights with $300 r/t tickets and those flights go away, they lose the seats on that plane that were being used to feed the international flights. If they lose feed to the international flights, those flights become no longer economically viable, and the airline can't sell the $5000 ticket.
A butterfly flapping its wings in Kansas City leads to the slow demise of the TATL network out of Atlanta.