Check out Binstock's January 15th column in Software Development Times, Integration Watch: The End of PERL?
Very compelling case, generally free of the kind of subjective rants that often characterize analysis of PERL's viability. I tell people to drop PERL all the time, but I don't often have as clear a case as Binstock presents.
A few years back, I would participate in the "Python vs. PERL" debate. That' mostly died down. You'll see questions like http://stackoverflow.com/questions/491380/should-i-use-perl-or-python-for-network-monitoring and http://stackoverflow.com/questions/150043/python-v-perl on Stack Overflow, but they're pleasantly rare.
The more common question is the Python vs. PHP vs. Ruby vs. some other language (PERL, Lua, Lisp).
Community Support
The issue seems to boil down to community support and leadership. A language must have a conceptual integrity -- it must be the product of one mind. If it's a camel (a horse built by a committee), then it becomes a complex, difficult to understand beast.
Reading up on the history of Pascal, it appears that the was a committee that worked on the follow-on language to Algol 60. Because of the success of Algol 60 a lot of people had a lot of things they wanted in the follow-up language. Apparently, the effort fractured into three camps.
Nick Wirth lead one group -- they produced Pascal. Another group produced PL/I. And the "official" group produced Algol-68. Which had a longer life-span, and enjoyed higher success? I think Pascal was more widely used than PL/I. PL/I was limited to IBM mainframes and VAXen for the most part. And I don't know if there was ever a working implementation of Algol-68.
Python has the Benevolent Dictator for Life to guide the language evolution. I think that's one of the key reasons for it's success. Strong, visionary, limited-waffling leadership and a community that agrees that one person should lead.
Also See
The ZDNet article, "Why 2008 was another great year in Web technology ," has the following tidbit.
For me, one of the more surprising developments of 2008 was the rise of the Python language. This rise was greatly aided by Google and the shift of its focus from Java to Python. Google's infrastructure relies heavily on Python. To drive home the point, the Google App Engine includes a development environment that does not include Java. With the backing of an industry giant, it makes me wonder how far Python will go in 2009.