I don't entirely disagree with the larger sentiments, but I worry about the tone of the word 'tinker'. That is, the Ruby world is full of playful characters, and often displays a spirit that is far from corporate. However, many Ruby (and RoR) apps are also serious businesses at this point. There are also many libraries that don't charge money, do exhibit that playful or exuberant spirit, but also provide hard-core real-world functionality (e.g., Nokogiri).
tl;dr The word 'tinker' is a bit trivializing (perhaps unintentionally on Martelli's part). The division between 'tinker' and 'enterprise' doesn't fully or properly cut up the problem space. It's a binary view of a multi-faceted world.
(For whatever it's worth, this is my view as someone on the outside of this whole situation. I use Ruby and Perl about equally, primarily for systems administration and personal projects.)