At work I come across a lot of Japanese text files in Shift-JIS and other encodings. It causes many mojibake (unreadable character) problems for all computer users. Unicode was intended to solve this sort of problem by defining a single character set for all languages, and the UTF-8 serialization is recommended for use on the Internet. So why doesn't everybody switch from Japanese-specific encodings to UTF-8? What issues with or disadvantages of UTF-8 are holding people back?
EDIT: The W3C lists some known problems with Unicode, could this be a reason too?