Not sure about your figures Domestos.
A quick google shows that BA's capitalisation is slightly higher (although exchange rate fluctuations could explain that), its revenue is significantly higher than you quote and its passenger numbers are higher.
BA also seems to be coping with downturn better than Quantas from a quick look. As to your logic, maybe QF and SIA are too similiar and would have too much overlap? I can see benefits from a QF/BA tie up
I am neither employee or shareholder of either, can't see too much impact on me as a passenger either TBH