As you said, the conversion of all these devices to being an appliance. The first thing that comes to mind in that case are things like DVRs, TVs, and game consoles. The computer is no longer capable of doing whatever the user wants, but only what the vendor allows them to do.

What you describe is essentially what Apple is trying to do, indeed given a hardware revision they could attempt to replace the standard desktop entirely for many people, and in place give them something relatively locked down. We're not there yet but Apple and Microsoft are driving hard in that direction, and I'm hard pressed to believe Google isn't as well.

I suppose this diverges from the original course of discussion (and is almost certainly off topic) but I think we need to be wary about having capability shifted out of our hands and into those of others