There is some difference between the Japanese Mobile Phone market, and the Smart Phone Market, in terms of jobs could be accomplished. The smart phone market was effectively launched when the Android/iPhone devices that could run third party apps, came about in 2007/2008. The disruption that these devices brought about was not to mobile phones, but to laptops/PCs, and should be viewed from that angle.
No, Japanese mobile phones could already do most of what you can do nowadays on a smartphone with web interfaces instead of application for most of the services available in Japan. They had defined a specific protocol for mobile phones web pages to make it easy to navigate and display information. Technically you did not need a PC for most services anymore - that's precisely why I am using Japan as an example. If you don't believe me, go back and check what Japanese mobile phones could do back in the 90s. They were not pretty, but you could do a whole lot with them.
