The natural progression of forcing people to use the command line is to turn them off using computers.
Now, the author is presumably a tech geek and the kids probably have some genetic predisposition to doing the kinds of things dad does, so I don't care to predict the outcome. Similarly, the dad may be a great and inspiring tutor. But my view is you wait and see what kids are naturally interested in and try to widen and deepen the paths they pick of their own accord.
It's quite possible that knowledge of vim and emacs and package management won't be the world's most valuable skills in ten years. Whaddya think?
> the command line is at least one layer lower of an abstraction than a GUI
Only if that's the way the system is architected. Maybe thinking that way is actually a handicap.