Status has nothing to do with how many of these seats are released. The difference is how AA sells A seats versus how BA does. AA has a lot of corporate clients which they have made various deals with. One is to purchase J and get seated in A. Another is to get a hefty discount off of A. From my understanding, BA doesn't discount like that. They do in other ways but on AA youre competing with a lot more people for the same seat. It's one reason, from my understanding, that vips were moved from A bucket to whatever is used now. Too many people competing for the same seat. Yield management used to open up seats if you had a paid ticket but I believe they stopped doing so and I wouldn't hold my breath.

And I believe you get 200% miles in BA's programme for flying in first. You can also put them into another one like alaska or qantas.