This is the big weakness of AA and OW. The other alliances offer extra baggage allowance.
Even for those in F without status compare US and DL at 3 bags at 70 lbs. vs. 2 bags at 50 lbs. I have a flight with a lot of luggage tomorrow and booked DL with a connection hoping for the upgrade (which I got) to avoid the excess baggage fees on AA (which would have made me ship things as they would have totaled a couple hundred dollars).