If you were only looking for a replication of a machine config you have running at the moment, without the ability to add extra packages, then you can create your own ISO.
This post https://www.reddit.com/r/NixOS/comments/y1xo2u/how_to_create_an_iso_with_my_config_files/ has more information.
This seems like a decent alternative in lieu of replicating the entire nix store.
Carve your config in stone! :)
I think you'd need to clone the entire nixstore or whatever. I made a similar post:
https://www.reddit.com/r/NixOS/comments/12m8ojo/how_big_is_the_nix_store/
So you would need a ton of disk space, atleast 200TBs
If a solar flare happened that knocked out the internet your computer wouldn't work anymore.
that knock out the internet for months.
This could have ended the discussion.
Search for "Carrington Event" in 1859. Were such a coronal mass ejection event to re-occur in modern days; it would be beyond catastrophic. The problem is not so much a loss of Internet as a loss of electrical power that could last decades. It would definitely fry any exposed electronics, especially semi-conductors. It would destroy power station transformers which are not easy to manufacture and would take many years to replace a large number of them. Providing you had power to run manufacturing.