Hmmm, this one I'll have to disagree with you slightly on in the interests of fairness
I did LAX-DFW a few weeks back on an MD-80 with a dinner service. Passing through LAX twice in 4 days, I found the Flagship lounge pretty good - self-service bar, decent spirits
and decent snacks including smoked salmon (which I have a huge weakness for and stuffed myself on for the routing DFW-LAX-SFO!), sandwiches, fruit, nuts and sweet snacks plus "chips"/pretzels. In fact, it was on par with a Terraces I'd say (err, and have said somewhere, sometime on here before, I'm sure

).
On my flight (nowhere near as long as yours), they did warm nuts (in-jokes aside, ^), drinks twice, dinner (a choice of two hot dishes - I had a really quite nice lamb meal with side-salad), bread runs, more drinks, coffee, sundaes (^^) and more drinks
For balance, the DFW-LAX a few days earlier was 'lunch' and was indeed less impressive (the F/A messed up FEBO so I was left with a crappy choice of some ham and cheese croissant thing back in row 6 instead of the first choice...though when I politely asked about this, she apologised profusely and loaded me up with a couple of bottles of wine to take away as "service recovery"

) and no sundaes/proper dessert either.
However, all in all, I was left with a very good impression (this was my first 'decent' length AA F flight, the previous ones had just been very short hops). DFW-LAX-DFW is roughly equivalent to LHR-HEL-LHR which I do quite a bit (as do you!

) and the price was about the same in the end. The seats were vastly better (as you note) but on my flights, the service offering was either roughly the same or superior to BA (and even AY

)...based on this one trip, of course.
Guess it just goes to show - route/crew/timing make all the difference, be it AA or BA...
Phil
PS Oh, and as usaul they pissed on BA from a great height with proper, enforced priority boarding