Honestly python won in large part because perl took over a decade to come out with perl 6. Knowing that there was a backwards-incompatible upgrade on the horizon shortly and having that be true for a decade meant that new projects in perl or major upgrades in perl were delayed and then shifted to projects in other languages. Python and ruby both were beneficiaries of this (especially with PHP going through a similar process with PHP 6 which took 5 years before being abandoned.)