Well worth ★★★★★.
I'm not sure that I can go with the *detail* of the story, perhaps because I'm not sure if the technology will be available "whenever" to, say, fabricate better fabricators -- though I'm sure scavenging would be a viable option -- or whether we'd have to reinvent the loo roll, the toothbrush, and dry stone walling. There is a helluva lot of necessary infrastructure behind even moderately-complex electronics these days, and if that was compromised, we may find the whole house of cards come tumbling down.
Despite decades working with IT, I must admit that the old romantic in me still has visions of hippy communes and dreams of the sort of Shangri-La, away from everything in the Himalayas (or at least the foothills), found in James Hilton's Lost Horizon.
Nevertheless, looking at the overall *pattern* of the story, I really can appreciate the realism, and if the opportunity arose I would be sorely tempted to "walkaway".
One thing that did throw me a little, on occasion, was working out who was speaking, without attributions like "Natalie said." Non-technical readers might also be scratching their head wondering what words like "pwned" mean, but that's not much of an issue, and definitions are only a click away.
As I say, Walkaway is well-worth reading ... and thinking long and hard about.