One big problem they had was that they felt that hosting multiple Python versions on a system was a sysadmin problem, not a language runtime problem. This is a

One big problem they had was that they felt that hosting multiple Python versions on a system was a sysadmin problem, not a language runtime problem. This is an issue because many platforms and products shipped with some python2 scripts. So a developer trying to use python3 needed to start by setting up a mixed environment on their own. Ruby could get away with crap like that because it wasn't widely used outside of Rails before rvm/rbenv was common. Setting up python3 as the default python could break certain Linux distros. Even today MacOS ships with python 2.7 as the default.