I don't think any of the above reasons apply. I was just in Mumbai and flew out on CX 750 to HKG yesterday the 12th July. The lounge invitation still reads BA Terraces/ Clipper Lounge, but the check-in agent manually crossed out BA Terraces. When I asked, she said it was because BA was renovating. Now I don't exactly know where the BA lounge is, but not far from the gate, there looked to be a lounge area, but it had no sign on it and it looked completely closed. So I doubt it's an erosion of Oneworld benefits or BA being dumb. As for the Terraces lounge in Miami, as per Oneworld agreements, AAdvantage members, even emerald equivalent members, flying solely on North American itineraries, do NOT have access to lounges. That rule does not however apply to members of other oneworld frequent flyer programs. Hope this clears things up.