People that want NixOS should absolutely be free to install it, I just think making it the default makes the system dead on arrival. There are hordes of people using Arduino's editor on esp32 boards because they don't want to learn esp-idf (not a judgement, Arduino works fine enough for most uses).
> I don't really understand why would the team that already got a full plate decide to also invent a whole new Linux system while they're creating their hardware device.
Honestly, I just wouldn't solve that. Nix makes the product way harder to sell, and home-building a solution is either a) an entire product all by itself, or b) shitty, in the "it only works on very specific happy paths" sense.
I also frankly just don't think it's a feature worth as much to consumers as it costs to make. At worst, it's a minor inconvenience to reflash a Pi card. If I'm really lazy, I just disable systemd services for whatever was on it and layer the new stuff on top. It's like 5 commands to get it back to "close enough to fresh".