Interesting magazine. Not to detract from its content - but are any of those technologies really low tech? Old computers, solar panels, and the various generators all rely on exceptionally advanced science and technology. It would take decades of research to recreate them from scratch. It's more about reusing/repurposing 'old' discarded tech. Or keeping high tech going as people would do in a post apocalyptic society…
But yeah, "doing more with less" is the focus here. Skip unnecessary cruft. Not so much avoid using (high) tech stuff.
Also note that in the realm of computing (or even general electronics), high-tech IS frugal, if used appropiately. Thx to Moore's law, switch-mode power supplies, RPi style computers (or microcontrollers on the low end), e-paper / OLED displays & similar fancy stuff. Doing without those would be wasteful, imho.