Ideally - however there are points where it's not possible yet. Bindings like pycairo are a good example. On windows a WHL can be provided. On Linux it can't

Ideally - however there are points where it's not possible yet. Bindings like pycairo are a good example. On windows a WHL can be provided. On Linux it can't - Cairo (which pycairo binds to) is shipped by the distro, and distros are free to enable or disable different features. Since the C bindings are linked to the cairo shared library, and that includes all the backends you can't build that and know if would work in a distro. There are two use cases for pycairo - in one you might not care what the system provides and if the pycairo who provided its own Cairo shared object, that would be fine. In the second use case you want to use the system provides Cairo, e.g. to work with Gtk. It's impossible to resolve this workout changing how Cairo itself works and it's API. The result is no pycairo whl on Linux, and users who have to install all the dependencies (which once go to pango you pull in Gtk, X, freetype etc). Cairo isn't the only example but it's one I know. A lot of these are libraries that bind system libraries and predate virtualenv / venv - when they were created compiling things was fine.