I think that's also a bit of an unfair comparison given the number of AUR packages you usually use on Arch. With nixpkgs there isn't a distinction between official and community packages.
I'm just saying that X% of arch official packages being reproducible isn't a complete statistic when many day to day things are in AUR, most of which are in nixpkgs not NUR.
AUR is unsupported, and the fact that nixpkgs decides to support everything is for them to decide.
Reaching for reproducible builds support in Arch is a more attainable goal than for nixpkgs. Properly maintaing 80k packages without regressions is going to be a lot more work in the long term.
