It's especially a problem with dynamic languages, the lack of safe refactoring makes changing the language very difficult. Everybody learned the wrong lesson

It's especially a problem with dynamic languages, the lack of safe refactoring makes changing the language very difficult. Everybody learned the wrong lesson from the Python 3 debacle. The lesson everybody learned was "Big language changes are bad, don't do them". Whereas the lesson everybody should have learned was "Writing code in a dynamically typed language is like writing it in stone, it's really expensive to upgrade it later".