I think you're really overcomplicating this if your use case is to make something installable from PyPI. Think of it like this: * "install_requires" in setup.

I think you're really overcomplicating this if your use case is to make something installable from PyPI. Think of it like this: * "install_requires" in setup.py = "I don't really care how you get this, or possibly even what version of it you get, just get this". * requirements file = "I have a known-good, tested and functioning setup using these specific versions, from these specific URLs, of these specific packages; I cannot vouch for whether other versions or other distributions of those packages will work".