Much has been made of the reversers not deploying until very late in the landing roll.
Because they are not required and their performance is not included in any normal performance data, I have never seen a chart of the effectiveness of a reverse thrust installation.
I believe all AA 757's have RR engines. Their reversers are relatively ineffective compared to other installations. And the idle thrust setting produces very little thrust (air or ground flight idle).
By comparison, the Pratt powered 757's have extremely powerful reversers. They also produce a substantial amount of idle thrust.
My point.....I think at the end of the day, the lack of spoilers and either a low or no autobrake setting may be the culprit. Yes, non-deploying reversers may have occupied the crew from verifying spoiler deployment. But I do not believe the lack of reversers until late on the rollout on this aircraft will be a major factor due to their relative lack of effectiveness.