It’s an immensely important and profitable route for BA. I have flown it for over 20 years on a regular basis. It’s such an important route for BA that they decided to enhance the ground experience for their premium customers by entrusting their lounges to American Airlines. There are plenty of other threads on this forum that can set out in detail what a catastrophic mistake that was. Suffice to say that I now cross the pond every month with Virgin, and would recommend you do the same!