The boat people are totally missing is this: sure, mobile is growing like crazy, but what we're seeing isn't the death of PC. What we're seeing is the filling out and explosive diversification of the computing ecosystem. The future isn't a "next platform," it's a whole ecosystem of devices serving specialized functions or function domains. For PC that's "personal computing" -- doing "big" stuff and "real work." For mobile that's mostly communications along with navigation, etc., the sort of thing you want an ultraportable micro-communicator for.
I own a tablet, a smart phone, and a laptop, and of the three the tablet is probably the one I could do without. The smart phone and the laptop are used constantly. But the tablet is nice for reading and note taking.