It doesn't help that the most popular titles in Japan over the next 12 months are all cross-gen. I bet we see sub ~10K PS4 weeks here and there over the summer.
First title I can even think of grabbing attention is Deep Down, and I'm still dubious about the title as a whole due to lack of details (though I'm not actively searching for details either).
Bottom Line: PS4 will be weak for at least 2 years, which is long enough to entrench consumers in other user experiences (mobile, phones, etc...). I am doubtful PS4 will reach PS3 LTD numbers in Japan, which will also make LTD WW more difficult to reach in turn.