> And yet, in many cases they are a productivity drain. Time is often better spend by writing testcases instead of chasing down type issues(more so if a language has a 'generics' or C++ templates concept), so that approach got favored in many fields.

From my experience I've seen that type hinting and checking provides a better ROI than automated testing. It is not either/or, you will most likely need some automated testing, even if it is just unit tests. But at the very least use types. It provides broader benefits than just catching stupid bugs and typos. At makes your code base much easier to understand and code paths much easier to follow.