> I just noticed the same. Is this intentional?

Honestly, no idea. I just copied how it was designed before, and had 
nothing to do with the original venv implementation.

At a guess, I think virtualenv did everything with a patched site.py, so 
when it was absorbed as venv it was retained. Changing this to calculate 
more in getpath.py was a goal of the rewrite, it just wasn't one that I 
wanted to do at the same time as the conversion, and am not particularly 
motivated to do myself anyway (when I hack install layouts, I don't use 
venvs at all ;) )