AA does NOT file their fares directly with each GDS. AA uses ATPCO, which is a third-party fares vendor. Other vendors include SITA and ABC.

Sabre fares are updated upto 9 times daily. There may have been a delay in the transmission of fares data between ATPCO and Worldspan, Amadeus and Galileo. That would explain the fare being unavailable in Sabre.

I would say that it's not a conspiracy theory, possible just a problem at Sabre World Fare which caused a temporary delay.

26% of WorldSpan is owned by TWA Airlines LLC, a wholly owned subsidiary of American Airlines Inc. 40% is owned by Delta and 34% by Northwest Airlines.