Dependency version conflicts and compatibility issues

Stateful virtualenvs with no way to check if they're clean (or undo mistakes), no locking of version resolution (much less deterministic resolution), only one-way pip freeze that only works for leaf projects (and poorly even then), no consistency/standards about how the project management works or even basic things like the directory layout.

The interdependency between libraries and the rapid evolution of the ecosystem can lead to compatibility issues and version conflicts. Developers may encounter situations where a specific library or framework they need is not compatible with the version of Python or other dependencies in their project. Resolving these conflicts can be a complex and time-consuming process.