Nix cache (cache.nixos.org) does in fact maintain older versions[0]. In fact, they maintain so much older stuff (binaries and associated source), that they are

Nix cache (cache.nixos.org) does in fact maintain older versions[0]. In fact, they maintain so much older stuff (binaries and associated source), that they are used in both research[1][2] and are having issues with gigantic cache size[3][4]. And yes, their reasoning implies NIH and just unfamiliarity combined with unwillingness to really understand Nix. [0]: https://discourse.nixos.org/t/how-long-is-binary-cache-kept-on-cache-nixos-org/11210 https://discourse.nixos.org/t/how-long-is-binary-cache-kept-... [1]: https://hal.science/hal-04913007 https://hal.science/hal-04913007 [2]: https://luj.fr/blog/is-nixos-truly-reproducible.html https://luj.fr/blog/is-nixos-truly-reproducible.html [3]: https://discourse.nixos.org/t/nixos-foundations-financial-summary-a-transparent-look-into-2022/28107/16 https://discourse.nixos.org/t/nixos-foundations-financial-su... [4]: https://discourse.nixos.org/t/the-nixos-foundations-call-to-action-s3-costs-require-community-support/28672?page=7 https://discourse.nixos.org/t/the-nixos-foundations-call-to-...