"For a certain segment of the Japanese population, the appeal of foreign cars has more to do with conspicuous consumption than with the cars themselves. Sort of the Japanese version of bling-bling."
bingo
"TOYOTA also launched some certain sub-make especially for local market such as SCION. Is it welcomed by Japanese?"
could say that, except that there is no scion in japan (afaik) and most of those models have been released in japan for years ie. the bb and xa
they came up with that name for us boneheads who might not think toyota wasn't a cool enough name, ie what was done with acura infiniti and lexus
props to mazda