The same will happen in the US, China, India and other parts of the world. In many parts of the world, cellphones already provide the needed connectivity to the Internet. Overtime all the daily (connected) functions such as email, downloading music, collaboration, and so on will be available on the handset to most of the people, and cheaper and more convenient than using a PC; it is clear why the role of PCs will diminish. And PC manufacturers must take notice of this, and adapt.
Read the complete article PCs being pushed aside in Japan (Yahoo! News)