I don't know about QF and all leaving with BA. As a lot of analysts are saying, BA seems to be struggling to gain some bargaining position by talking to KLM but there is no way they can offer a compelling alternative to AA.

There are cross-holdings etc. between QF and BA but the key is also access to US market and AA and UA are the dominant players here. CO and NW sued each other until things got settled (with some govt anti-trust meddling of course!)

NW/KLM do not come close to the network that AA alone (now with TWA) offers. I think the core of OneWorld will survive irrespective of BA moves.