I don't think this is a good argument, because eg CPython was the reference implementation of Python since day 1. In other words, since the very very first day

I don't think this is a good argument, because eg CPython was the reference implementation of Python since day 1. In other words, since the very very first day of python, people could tell a new python user to grab that one very specific package from python.org and go ahead until he is able to judge the different implementations out there, which solves precisely the problem mentioned in the article. Same goes to an extent for Java and PHP.