Can you give an example of a real ecosystem that can't handle such a conflict? In my actual experience, the package manager will either automatically use the la

Can you give an example of a real ecosystem that can't handle such a conflict? In my actual experience, the package manager will either automatically use the latest version, or in one case has more complex rules but still picks a version on its own (but I stay away from that one due to the surprise factor). Your argument has force against bad package managers and against using very strict dependency requirements, but not against pinning dependencies sensibly in a good ecosystem. The only conflict I've seen that can't be automatically resolved is when I had some internal dependencies with a common dependency, and one depended on the git repo of the common dep (the "version" being the sha hash of a commit), and another depended on a pinned version of the common dep. Obviously there's no good way to auto-resolve that conflict, so you should generally stick with versions for library deps and not git shas.