to be clear, I don't think anyone is using all of these libraries in a single project. Most Backbone web apps probably use 2-6 of these repos. So the fact that some of them have gone stale is not in itself a problem, and is normal. The fact that nearly all of them have makes it much more difficult to build sophisticated web apps with Backbone. Everything non-trivial has to be done in an in-house ad-hoc basis, or using lightly maintained 3rd party code.
I didn't read your article as making that case. My riff was more on the exponential size of the dependency space. Even if someone is only using 5 external libraries, if one of them is among the 25 listed, the dependency chain can easily become burdensome.
To a first approximation, I think the default for JavaScript development is to treat taking on dependencies lightly. And because the JavaScript zeitgeist moves from project to project so quickly, there's often no historical base to take on supporting open source projects when the original author moves on. I mean Jeremy Ashkenash can take a motorcycle trip in part because of his decision that Backbone is not evolving quickly. The idea that things must evolve quickly equates to more work and more work is a recipe for burnout.
