Earlier quoted context omitted.
You're right. However, there comes a point where we don't need yet another framework, or productivity app, or another project management tool. I also think the author is addressing people who build "thin value" startups as well, not just developer tools. Like Color, or Farmville, or Diaspora.
People who build things that "we don't need" get the message when no-one uses their product and they run out of money. But it's still a valuable process for them and everyone else, as long as they learn how to build things we do need.
The point of the article is that it's easier to build and profit from these wants, even if they're not truly beneficial to people outside of the developer community.