This seems like an overstatement to me, at least when it comes to the practicalities rather than the machinery. Single-user, unprivileged Nix wasn't very hard f

This seems like an overstatement to me, at least when it comes to the practicalities rather than the machinery. Single-user, unprivileged Nix wasn't very hard for me as an undergraduate student a decade ago, and there are much better options for achieving that nowadays.