My understanding was that there were 3 frequencies a day on that route and they rolled the pax over to other flights. So BA's load factors probably went up. So oddly enough they have probably profited from it, unless the loads were significantly over 66 percent on all three flights to start with...
Atleast in the short term. In the long term, who knows. Bookings may have dipped on the UK side of the flight, but all evidence is that the US side traffic is rebounding quite rapidly still...
Cheers
Wino