> possibility of all-mighty failures caused by adding the extra layer of abstraction and complexity
In the end, I think all distributions ends up with similar layers of abstractions and complexity, mostly regarding packaging, but sometimes also other components.
What I've found when using NixOS compared to Arch, is that if I screw up my Arch installation I either need to sacrifice my time to try to fix the screw up (which sometimes adds spending time just learning/reading about some concept I don't know about) or I need to recover from backups, so I can get back to work.
With NixOS screw ups, I simply choose the previous version on boot and I'm "recovered". Leads to me getting back to what I was doing faster, but missing the opportunity to learn my own personal stack better. But not every moment needs to be "understand everything 100%", which in Arch-land, tends to happen, otherwise you continue to screw up.
Although I'm still on the fence of upgrading to NixOS because the OS as an concept + it's own language is still not easy to learn, especially for more advanced usage, it's getting closer each day to just dump Arch and start using NixOS full time. Mostly because the reproducible nature of the OS.