I think the least that distros can do, is allow listing all packages and system settings in config files like .toml, rather than having to type in every single package to install, or click through system setting GUIs to setup. Would that require using a whole programming language or system like NIx?
While NixOS works much differently from most distros, that’s the only reason I use it: package and system settings in text files. If I fix something, it’s fixed permanently, I don’t need to hunt down files in random directories if I want to change a setting. If I ever need to reinstall the OS I don’t have to write dnf install every single damn package and manually setup all that up all over again. Having daily-drove Windows macOS & Fedora as throughout the years, my setups have felt hacky as well as houses of cards as I’ve wanted or had to set them up again (I don’t mean Fedora specifically, but distros in general).
Basically it feels insane that it’s the way most linux users and servers in the world operate. If I, a humble computer hobbyist can figure out Nix, why don’t more users do so, and why is Nix so niche?
Short answer: Because it would be bad software design.
More detailed answer: I can definitely understand the feeling but a large part of it is that text files are not databases. Trying to use them for that purpose leads to quickly running into a brick wall of scalability problems. Seriously, that wall is hit faster than one might expect.
Why use a db in the first place? Well, when a package manager installs a package, it does a lot more than install files in their specified paths and store the name. Every package also has a ton of metadata. This includes everything from the software version number and versions that it obsoletes to repo that the package is from to signatures to verify package authenticity and checksums to verify file integrity.
Storing all of this info is the sort of thing that databases excell at and text flatfiles are terrible at. The db also includes integrity checks for itself. Since the data is already stored in a db, also storing even a subset in a flatfile would be poor software design as it is unnecessarily wasting storage space in a manner that would perform significantly worse and is much more prone to data integrity failures.
So, how do you work around that for backup? Just script a dump of the installed packages from the package manager. It’s trivial with apt and dnf/yum. Then, store it with dot files in your backups.
To restore, I’d recommend Ansible because it works nicely with lists of packages and has minimal dependencies.
If you don’t want to interact with the package manager and like domain specific languages (or don’t dislike the syntax), just use Nix and be done with it. Noone whose opinion matters is going to bully you for the choice. If, like me, you strongly dislike DSLs and the Nix syntax, the choices are pretty much Fedora Atomic, GUIX, and/or Ansible.