Other airlines, such as BA, will happily accommodate you in an earlier flight, free of charge. They do this for both national and international flights.

AA, on the other hand, charges a fee for confirmed change, and only offer this 'service' in a sub-set of their flights. They do have a lot of restrictions too: https://www.aa.com/i18n/plan-travel/...day-travel.jsp

Is this related to old IT systems, or just another Customer Service Oriented (TM) attitude?