The Post-PC devices[1] (tablets / smartphones) are it for the majority of folks from here on out. They are easier to own since the upgrade path is heading to buy new device and type in my password to have all my stuff load on it. If I want to watch something on the big screen, I just put a device on my TV. Need to type, add a keyboard.
The scary part of all this is that some of the culture of the post-PC devices are infecting the PCs. We see the restrictions on Windows 8.x with the RT framework (both x86/ARM), all ARM machine requirements, and secure boot. We see the OS X 10.8+ with gatekeeper, sandboxing, and app store requirements with iCloud.
The PC culture was defined by hobbyists before the consumers came. The post-PC world is defined by security over flexibility. Honestly, 99% of the folks are happier this way. They want their stuff to work and not be a worry, and if getting rid of the hobbyist does that then fine. PC security is still a joke and viruses are still a daily part of life even if switching the OS would mitigate some of the problems.
I truly wish someone was set to keep building something for the hobbyist[2], but I am a bit scared at the prospects.
1) Yes, I'm one of those that mark the post-PC devices as starting with the iPhone in 2007. It brought the parts we see together: tactile UI, communications, PC-like web browsing, and ecosystem (having inherited the iPods).
2) I sometimes wonder what the world would be like if the HP-16c had kept evolving.