That’s my experience using Nix in a nutshell, every time I’ve tried to use it.

Flakes, home manager, half the packages I need, etc

It's a political thing, flakes are not going away or changing radically. Though the CLI commands aren't "stable" (guaranteed not to change wise). I read somewhere that someone of importance believes and thinks flakes will be enabled by default in 23.11 already.

So...devbox adopted flakes before Nix did? lol.

Does anyone already rely on LLMs way too much? Yes, but nix is a lot more predictable than LLMs are.

It's not for everyone, but when you work with infrastructure and can guarantee that the software the developers build is the exact same version you're running for them it feels good to have that conversation out of the way already.

The thing with nix is that features are experimental for a very long time, even though they are quite solid. It seems like it is mostly used so they can still make changes, like the CLI options or the names of attributes in the flake. The effort to use it is just adding extra line to the config.

Even after it passes the experimental stage, I doubt they'll drop support for the default install/config method using configuration.nix. Flakes will just another option but not required.