Comment # 3 on bug 1071941 from Jan Matejek

It has been like this since, uh, before we started using pip, i think ;)

There used to be a patchset changing the default install location for distutils
and setuptools, which was dropped because it brought more problems than it
solved. So we never explored doing a similar thing with pip. Maybe the
landscape there is more reasonable, seeing as other distros are doing this.
I'll have to look into it.