I think this is a case where the imagination is much, much better than the reality.
For the mobilization of technology, miniaturization has had a lot of benefits, not just in the technology, but in the accessibility. Having a desktop computer instead of a mainframe was huge. It brought the computer to the home. Laptops becoming viable was huge again. It untethered the computer from the wall. For most of the planet, we're still in the midst of the massive leap that is smart phones. It put a computer in the pocket of billions of people.
Beating that is hard. Smart phones are the most accessible, most powerful devices most end users have ever used. We take that for granted, and we take the time it took to get there for granted. It took 25 years of desktops to get real, decent laptops (personally, I'd say mid 90s). It took 25 of laptops to get real, decent smartphones (again personally, I'd say ~2010ish).
Like it or not, we have another decade to go probably before the technology is there for the next evolution in personal computing. But the problem we have really is that there's not another leap as far as accessibility is concerned. Smart phones work places where laptops can't. Laptops work places where desktops can't. Desktops work places where mainframes can't. Smart phones can work anywhere. Taking the computer from the datacenter, to the home, to your backpack, to your pocket is huge. Is the next step from the pocket to your wrist? To your face? Is it worth it? Is it really that much better?
