All aircraft make many flights a day. Just moving one flight would disrupt that chain of flights, so it's extremely unlikely that "a single one time change" was made.

Airlines are always evaluating flight loads, competition, etc., and evaluating changes to number of flights, type of plane, destinations served, etc. Any time a change is made, the process that optimizes the use of aircraft, crew, etc., etc., need to be executed. An airline can't just add an extra DFW-ORD flight. It needs to have a plane to fly, that comes from somewhere, and goes somewhere after. Same with crew. Thousands of pieces of equipment/crew need to be optimized. And when one piece of the puzzle changes, it has impacts on other parts of the schedule.

So the reason for the "madness" is a company trying to run a profitable and efficient airline.