It's not "limited" when a high school makes it a requirement for graduation, just as algebra, chemistry, and the six best-known Shakespeare tragedies have long been requirements. The college I went to made Introduction to Programming a first-year prerequisite even for people not going into computer science. As things like that filter down from college into the third and fourth years of the college-prep track of high school, much as calculus has done, we'd better hope that the Raspberry Pi stays in production.

At some level, it doesn't have to be a "good" programming platform, just a programming platform at all. Apart from Codea, the iPad has failed even that.

Consider a high school student who owns an iPad and then discovers that she has to take a programming class before graduating, and that the tools needed for doing homework aren't available for iPad. What's the next step? Sell the iPad and buy a low-end PC?

Jbolden mentioned that analogy earlier. So what should someone do who only occasionally needs to use a truck? I seem to remember that a lot of people have been buying SUVs because they can act as a car most of the time but as a truck when needed.

But incompatible instruction sets. If an operating system is non-free, its publisher has to make a business decision to port the operating system to a particular device. And Microsoft has made a business decision to lock third-party desktop apps out of the ARM version of Windows, making the device less useful when docked.

What you say would have been more true prior to Apple's adoption of x86 in 2006. There exists a project to port AOSP to x86. But a lot of popular Android applications are built using the NDK and compiled only for ARM, and the publisher of each application has to make a business decision to include x86 binaries in the APK.

Other than that Apple would frown on the interpreter needed to run spreadsheet macros under iOS.

And I have yet to meet another regular user of a home theater PC within the sample set of my extended family. But as you're aware, that doesn't mean they don't exist, just as the lack of people switching from PC to iPad among your sample set doesn't mean people like this don't exist:

My daughter told me that if I bring in my old computer and my printer, I can trade my computer for an iPad, and you’ll set it up with my printer.

I agree with you that a desktop, laptop, or tablet computer running Windows (for x86 or x86-64), Mac OS X, GNU/Linux, or Android is a personal computer. An iPad not so much because the "person" who owns an iPad lacks control of what "computing" is done on it without buying an additional Mac and paying a substantial annual fee. (I say "additional" because the majority of PCs in use aren't Macs.) Out of the box, the owner is forced to delegate this control to Apple.

The biggest distinction in practice between Android and the desktop operating systems is that Android's window management policy offers no standard way to split the screen into areas for different applications. But I'll admit that's not essential to the definition of personal computer because it also applied to most 8-bit personal computers, Macs pre-MultiFinder, and IBM-compatible PCs pre-Windows.

I thought that because of patent royalties and greater complexity of processing, a cellular radio capable of data cost substantially more than a cellular radio capable of only voice and text. What am I missing?

So what unlocked Android phone do you recommend as an alternative to a $299 iPod touch?

Either kids, or a grown-up and his girlfriend, or a grown-up who has grown-up friends over for some other reason and they get an itch to play a video game together. PC multiplayer has historically required a separate PC and a separate copy of the game for each player because PC monitors have historically been physically much smaller than TV monitors. This size disparity began to change in 2007 once TVs gained PC video inputs and PC monitors shot up toward 23" to use cheap mass-produced TV panels, but there's still been enough inertia and enough ease-of-use advantage for consoles to keep their hold on the living room.

Then the owner of copyright in the sound recording can distribute lossy files to the public and distribute lossless files only to people who have bought a license to make remixes.

Not if an application depends on a particular peripheral with an XP-only device driver. ReactOS, an environment for running XP device drivers, isn't quite as mature as Wine.

Let me Bing that for you: Skype headset

https://pineight.com/ loads in Firefox on Windows XP and Chrome on Windows XP, but it gives a certificate error in IE on Windows XP because IE on Windows XP doesn't support Server Name Indication, a feature required to use SSL with name-based virtual hosting.

Of course you can make calls. Just open the Skype app from the Start Screen and put on your headset.