Of course, specific projects might not be covered, but I've seen a lot of people go "ok, just to be safe I'll use 2.7 in case down the road I get to need anythi

Of course, specific projects might not be covered, but I've seen a lot of people go "ok, just to be safe I'll use 2.7 in case down the road I get to need anything that's Py2 specific". In your case you know exactly what your needs are, and that they're unsupported in Python 3, but I'm sure that many of those 70% Py2 projects could run just as well in Py3.