Romulus, you have used the figures from my research and calculated that more people fly on Jetstar on the Japan route than on Qantas but that doesn't prove a thing. Jetstar are flying 4 flights a day to Qantas's 1. In Sep 2006 Qantas were running 6 flights a day with higher load factors than Jetstar do now. Many of the lost customers have moved to JAL.
You can say people haven't been forced to fly Jetstar because nobody has a gun at their heads which is correct as a statement but the real issue is this. People have been forced to fly an airline other than Qantas because apart from one flight a day, the opportunity to choose a Qantas flight has been taken away (that is the extra 5 flights per day).
Many of the pax who have been forced away from Qantas have chosen Jetstar but a substantial number have also moved to JAL. That is why they are now leading Qantas and Jetstar for load factors on those sectors.