If you are just trying to get going I suggest installing a fresh version of Linux on an external disk. I had similar issues trying to get development going on Mac and Windows. I'd say unless you have a compelling reason to fix your current
environment, then just start fresh. (boot from another disk or USB if you have too)
I'm not picking on gnuradio here but, software installation in general is in a very sorry state and declining quickly. This is why overlays and platforms like coreOS and docker have cropped up on recent years. I've run into dependency issues
with python on other projects. There have been countless attempts by people to try to fix it. Most of them try to setup a "sandbox" installation of python for a particular application. The problem has gotten so out of hand that the easiest answer is, just
do a fresh install wether it be a VM or docker, for new apps.