I'm based in Japan right now and Qantas is doing a ton of advertising here. There are Qantas billboard trucks running around and entire trains have been decked out with Qantas advertising. Looks like they are really trying to drum up some business.
The economy is definitely slowing down, spending is way down and money doesn't grow off the trees like it used to several years ago... The exchange rate is also really bad, I'm moving back to oz soon and really not looking forward to exchanging my savings!
I definitely agree with everyones comments on Jetstar not working in Japan, service is a huge part of the Japanese culture and people just expect more. The whole idea of an LCC is completely foreign, there aren't even any domestic LCCs.
I'm not exactly sure about this but I presume most of Jetstars sales are online. Here in Japan the majority of people still go to the travel agents, so unless they really push it the Japanese will tend to stick to the more traditional legacy carriers.
I also find that fares are a little expensive relatively. I had some friends looking to go on vacation, they looked at airfares and it was cheaper to fly to the states than it was to oz. And when I go to book tickets from Japan, Qantas is always the most expensive option by far, sometimes double the lowest fare.