I, too have had calls from BA when my business dropped off. However, UA is possibly in a strange position. IMO it is a combination of things which puts UA so behind the pack as well as uncaring
A) SHARES - I truly don't believe they have a clue as to which customers have left, which one are new, etc
B) THEY DONT CARE - This a certainly part if it too. Planes are full. They could care a less who's in the seats. Ifpn fact, based on statements that have come from Jeff in the past, I would bet he prefers these seats be filled by other then Elite passengers so he can collect all those fees. This way work for now, but the first time passenger traffic drops off, UA will feel the pain.
C). He (jeff) is in denial. He does not believe that many Elites have left. I agree a little w this statement. I don't think as many left as some of us think. However, that's no excuse. They should fight for each passenger