If you constantly work on the same code base day-in, day-out, breakage through the language or libraries is much less of an issue. You can keep up with current developments in the language and/or libraries, and update as necessary. Incremental changes are not a big deal, since you’re always around when they happen.

If you tend to write code once, and come back to it months or years later, breakage is a huge issue - why is the code that was working perfectly well in 2019 broken today? Why do I have to now fix 4 dependencies in order to do what I actually wanted to do (make some small change). This is the reason that I tend to write all my own code in TypeScript projects, but for my Clojure/ClojureScript projects I am much more happy to pull in the occasional library.

I would say that the “don’t break things” culture is less about static vs dynamic types, and more about the style of software being written and the maintenance expectations.