IIRC, the shift to more fuel efficient cars was a response to the consumer trends that followed the fuel crises of the 70's; kind of ironic that we still don't see truly affordable, fuel efficient vehicles on the consumer market, and the price of gas has once again hit record highs.
My point is that if the OP (who hasn't posted since December) wanted to know what kind of cars Japanese people buy and why, he should look to consumer reports, or at least, the kind of cars that sell in Japan, rather than polling a bunch of foreigners.