Sun has always seemed to have almost the right idea. 

Services will be big, everyone knows that.  How does he go from that to "PCs are so yesterday, everyone will be using cellphones instead"?  Services aren't worth much without a decent user interface.  And as much as I like mobile stuff, the little screens are just barely usable for most things, and not a lot of fun.  Sure they will improve; some are already sporting 640x480 screens, but they are still tiny, and to be readable, the font sizes must be so big that you can't really show a "normal" 640x480 on them. 

The user experience is what counts, not the technology or service that provides the experience.  I think replacing PCs with cellphones will happen around the same time TVs are replaced with cellphones.   Approximately never.