Many folks have followed OneWorld exALG fares over the years so I will post here rather than start a new thread.
The fare structure was lucrative, same sort of thing as ex KTM for a while where you could get R or D fare basis for the price of I fare in many markets. That means you can cheaply upgrade to AA F, nothing to write home about I'll concede, but not a bad thing if the fare is this low.
AA unceremoniously yanked all the exALG R and D fares to the west coast of the US, but effective Oct 2020 has reintroduced an R basis fare on some routes that totals to about US $1611 for the roundtrip. I found it to work easily for ALG-SEA, that is a great fare, $800 per direction in biz or throw some miles at it and you are in F. Schedules suck now and so no LHR-LAX to get a long ride in F on the 77W, but may be worth it as more 77W flights get reintroduced. Base fare is $1134++ and depending on connections is generally in the $1611 range.