I did not say that hobbyist packages which are used by few people and are unstable experiments should be kept stable at all costs. But you see the linked discu

I did not say that hobbyist packages which are used by few people and are unstable experiments should be kept stable at all costs. But you see the linked discussion about stability in Nix is about packages like opencv, pillow, boost, pytorch, tensorflow, kubernetes, and I would expect them to behave professional. And as said, as long too few people actually respect semver, it is pointless to suggest to use it, especially if the authors of a package do not know what a breaking change is, do not know how to avoid them to happen, and do not have a documented and specified API in some way. If you don't have an API, you can't use semver.