Some of the B744s are in great shape, some quite poor, with 52 aircraft built over an 10 year period, there will be differences. The situation on the day though was completely unacceptable for the fellow who got wet, though in my experience this is not typical of the BA economy product.
Only one of the three daily LHR-LAX routes has just been upgraded to a B777-300ER, the BA279 / 278.
I did four sectors on Delta and two on American last month, and the transatlantic sectors on the Delta B767-300ERs were quite retro with the best not surprisingly being a new B777-200LR on a domestic sector.
What was the date and we'll see what aircraft was involved, then we can comment on age etc.