I think that you are right, but I'd say that the underlying issue behind these points is the number of people working on the project. Dynamic languages mean that you can rely on implicit knowledge, rather than be explicit about everything.

If your project is just _your_ project, then dynamic languages let you start faster and produce quicker. Apart from anything else, these languages attract people who value productivity, so clunky tools don't survive in those ecosystems.

Of course, almost no successful project stays in the hands of just one or two people: new developers come in, or it's Open Source and more people show up, as well as the "drive-by" contributions.

IME, Ruby on Rails projects scale to about three core developers before you start to feel pain. The strict conventions of the framework help mitigate the communications issues of keeping people in sync. Beyond that, the implicit knowledge that is not in the codebase is harder and harder to scale.