3. PHP is also a rather good language these days. However, it tends to be viewed as a website tool and not as a general purpose programming language. That might not be fair, but appears to be true. PHP also suffers from a few quirks (all those dollar signs).
4. The Python 2->3 transition was hard for many folks (not me, I started with Python 3). However, it is mostly over by now. The transition did bring one rather large benefit. Python 3 fully supports Unicode. The same can not be said for a rather long list of languages.
5. As the author pointed out, Ruby has always been handicapped by its origins in Japan. That may not be fair. However, it still appears to be true.
6. Perl is just a relic from the past. Essentially nobody takes it seriously these days.
What this amounts to is that Python is the “last man standing”. Hence, the rising popularity of Python (outside of the browser).