Does anyone have any thoughts?
Note that there is one situation where scripts for multiple Python versions reside in the same directory: per-user site-packages (PEP 370). If you install a package which has scripts and you don't write versioned scripts, a second installation of that package (with a different Python version) will cause the first script to be overwritten. Much of the time this won't matter, but there might be scenarios where it does.
It may also give a problem when uninstalling, or when verifying the installation (as the hash of an overwritten script may not match what's expected, as per the original installation).
To avoid overwriting, one would need to write versioned scripts *only* :-)