Money or lack thereof. The merger of PS and PI resulted in USAir having a hodgepodge of various aircraft types and the beginning of financial losses began in 4th quarter 1989 and continued for years. Several high profile accidents quickly marred the reputation and "USScare" suffered the loss of market share. Stephen Wolf began the transition to the Airbus fleet and aircraft capable of the markets you have mentioned were in the fleet already,
the 757's to Hawaii and the early introduction of the A321 was the FL and transcon aircraft by 20001.
Wolf left and by 2005 the financial situation was dire and the airline came close to shutting down.
In steps the HP group and the rest is history. Under the direction of Doug Parker and Scott Kirby US eventually became profitable after years of losses along with the furloughs of hundred of employees and a major streamlining of the operation.
US has had a poor reputation and many here do not hesitate to mention how they hated US and that is was the "worst" airline ever. It should be recognized as well it is a miracle the airline has been successful by its own determination and grit and the efforts and hard work of many good employees.
I now hope AA eventually becomes "Something Special in the Air." again. It wasn't at the time they used that slogan and it isn't there yet. It can be and while my travel on AA has been pleasant and uneventful, as a retired employee my expectations are focused on 32 years of experience in the industry tempered with patience, a higher level of understanding and a great travel program to enjoy with family and friends.
I was dedicated to Piedmont, loyal and hard-working to USAir/ Airways and respectful to AA and its history. I want it to succeed and hope it regains the stature and respect of being one of the USA's pioneering airlines that offers unmatched reliability, safety, innovation and service.
That is a full time job for any airline, day in and day out by a group of dedicated employees at ever level in the company. Make American great again!
watch what you want. you may get it.