I may have worded it poorly, but I do agree with your last comment.
The point I so poorly tried to make, is that there isn't any statistically accurate way to compare the last 30 years at CX, or QF to United. One can argue bogus statistical comparisons, but without the requisite data (ie one airline with an insufficient number of departures for comparison), it's not valid.
Based on this, I see no reason to claim the US airlines are safer than QF/CX, just because they have more departures to their name...