A new release every 6 months, and the old release almost immediately stops getting any more updates.
Also, from a vulnerability management perspective, NixOS is terrible. If you have some compliance monkey at your company that demands CVEs get resolved regardless of impact, NixOS is the wrong choice. Yeah, they'll patch CVEs that are truly impacting, but for non-impacting CVEs, they're not nearly as interested at backporting fixes as Debian or Ubuntu. From an actual security standpoint, it's fine, but if compliance requires you to resolve CVEs within a certain period of time, NixOS will fail for you.
The same reason you don't use arch linux on servers. Some distros are simply better suited for servers. We do have talosos for k8s and we (used) to have clearlinux.
rather than being theoretically better, it's simply the standard way of running servers. Nobody stops you from using nix or even arch on servers, but nearly all of installations, enterprise packaging and "officially" supported distros are debian/ubuntu/centos and has been like that for a really long time.
Nvidia for example won't give you any support unless you use specific kernel versions on ubuntu.
Basically, yeah.
A new release every 6 months, and the old release almost immediately stops getting any more updates.
Also, from a vulnerability management perspective, NixOS is terrible. If you have some compliance monkey at your company that demands CVEs get resolved regardless of impact, NixOS is the wrong choice. Yeah, they'll patch CVEs that are truly impacting, but for non-impacting CVEs, they're not nearly as interested at backporting fixes as Debian or Ubuntu. From an actual security standpoint, it's fine, but if compliance requires you to resolve CVEs within a certain period of time, NixOS will fail for you.