But The fundamental data structures/algorithms don't change and the problem solving skills don't change. For example, get an Oculus Rift dev kit, fool around on that for a few months when the consumer version comes out you'll probably have more work than you can imagine. It's the same pattern.
On the other hand, Linux kernel programming, which is what the author mentions, hasn't changed that much over the years. What the author seems to bemoan is that the developers are letting those core skills slide because they become dependent on the tools they use in their day-to-day jobs. But actually, I'm not convinced that the mediocrity of the candidates was due to decaying skills. They may not have been particularly skilled to begin with. Experience doesn't necessarily correlate to competence, after all.
I learned Android on my own time, because I liked the idea of a Linux-based phone OS. Most of the jobs I've gotten have been EXACTLY because I've been playing with the right technology on my own time. OP is right on, and VexXtreme is making noises like a mediocre developer who has a chip on his shoulder.