AA scaled back their European presence massively, it's a mere fraction of what it once was. The reason they have a large presence today is because of the merger with US, much of the existing network was built by US as AA retrenched. So MAN went from ORD/JFK on AA and PHL/CLT competing on US to what we have today where even ORD was seen as at risk due to old equipment and unreliability. The JV with BA meant they could funnel so much more traffic over a one stop LHR at less cost from the US and led to AA only having a major presence in a few markets. MAD has five daily but MAD is a Oneworld homebase for Iberia.
Delta sent the message to market by leaving the market to VS, United are hanging on but have a decision to make on equipment and AA seem to do well on PHL and ORD is more stable now. As for BA? That's what the shuttle is for alas.