This is the case for me as well. I tried NixOS this weekend, and even though it has more adoption than Guix, it still does not have 100% coverage of all software I wanted. That said, the packages I did install were pretty up-to-date. I guess NixOS is as close to “critical mass” as we’ve got when it comes to this type of OS. But if I were a wizard devops type person with more time, I’d probably enjoy Guix more.