Yeah I can't see BA running it either. As for economics of the route, the prices and aircraft loads haven't changed much in the time the route has been running. Taking into account the frequency reduction.
With Transaero gone this leaves BA and Aeroflot which is not great. Maybe S7 or Wizz would be a good addition. Easyjet should not be allowed to retain the route licence if they are pulling out. And maybe they're chasing "easyier" cash elsewhere.
Been travelling there for years originally on the Bmi.