They really are remarkably bad. BA286 (SFO) went tech last night, with a broken fuel pump. Fair enough, it happens. Quite a bit of space on the two 747s today (which are scheduled to leave earlier), but the airport desk simply refused to rebook. "You have to call the telephone line."
The US phone line was closed, of course, so I called the UK. "Oh no sir, we couldn't rebook you. You'd have to see an agent at the airport."
I tried again this morning, and this time the telephone line was more accommodating. "Oh yes, we can put you on the LAX flight." Great! "You'll have to get to LA yourself though." Why? Can't you just put me on the AA codeshare? "Your flight is only delayed (25 hours), not cancelled."
What's the point in having a huge four-airline US-Europe network if they're not willing to put me on anyone else's plane?
This is one area where AA is stratospherically ahead of BA.