This doesn’t really make sense, at least not without a lot more definition of what you mean by “distro” here (if PyPI is also a “distro”, then sure, but I’m pretty sure you weren’t implying this 
)
Perhaps what you mean is “the Conda environment and its Conda-installed packages is the distro, and pip-installed packages go into site-packages”? Which does make sense,[1] but only actually works if pip is searching both directories and then choosing to install only unsatisfied requirements into its own directory.[2] Without this, it’s just as messy as a venv based on a Conda env would be today.
The best way to make this work really is for Conda to build its packages directly into Lib and not Lib/site-packages, which it can easily do - it’s just how the files are packaged. It also saves having to convince Python to find another search path on startup, which is also way more messy than it should be. But of course, the transition costs are pretty significant here, even if the end result might be smoother in some ways.