Perhaps I wasn't clear. What I meant is that in environments that do support tree-shaking, you can depend on large libraries, and/or many small libraries, and the run-time impact will be no more than if you had written or copied and pasted just the functionality you need.
This could be very true, but to show the causality it is necessary that tree shaking abilities of language/tools on average precedes widespread use of huge dependency trees. It could be in reverse. That is when for some unknown reasons multiple dependencies appears, tree-shaking tools follow and it is just easier to create them for static languages.
