The requirements of a package manager for application development are different than the requirements of a package manager for a system. The system packages nee

The requirements of a package manager for application development are different than the requirements of a package manager for a system. The system packages need to play nice and be compatible with all other software intended to run more or less permanently on the same device. A package manager for application development is installing dependencies for building and testing an application meant to be run on other devices. What are you supposed to do if you're developing an application and you want to use the latest version of requests for Python but some system utility your OS relies upon is using the distro-packaged version of requests, which is older? Your distro package manager doesn't give you the means to install dependencies on an application-by-application basis. Either everything uses it or nothing uses it. So you get virtualenvs. Back in the old C world, you would have just built and installed some .so files into a project-specific deps directory and set LD_LIBRARY_PATH when running your application for testing. virtualenv is doing exactly the same thing but automating it. And, of course, there is now conan for native libraries if you're still doing C development. Heck, rpm won't even let you install into your own directories if you're lucky enough to get a relocatable package because you have to be root to acquire the global rpm db lock. What distro package manager lets you install temporary dependencies on an application-by-application basis? Possibly Guix?