Interestingly, earlier in my career, most of the developers I worked with were also capable at system administration, and could easily fill that role if needed.

The sysadmins during that time were quite capable, but had no desire, or an admitted lack of ability for a development role.

It is an interesting phenomena to observe.

Despite its clear fit with the current hotness of immutable systems and functional programming, I don't think I've seen anyone in for-profit industry on a Nix/NixOps stack.