That's because it's an 8 bit computer, my dude. Back in the old days, when "the internet" was still a military project, and you'd phone up your local BBS at 2400 baud on a POTS with suction cups; that's all the little people had access to as recently as the early 80s. And as other people said, there are apparently many of them around, and they run on shit power supplies.
It's a cool idea, but obviously it requires both cheap and dirty hardware implementations and a paper manual. Pretty sure "hacking" will be low on the hierarchy of needs in the event of apocalypse. Also pretty sure something like CP/M would be more useful. I know where there are CAMAC crates with Z80/CPM punched card/paper tape readers that would probably do great in a post apocalyptic environment.