Python is used not only because of its conciseness. It’s also used because many people don’t want to deal with types and complicated software engineering in general, so they will have more time to spend on the business domain. That doesn’t scale to big programs, because for big programs you need proper software architecture and strong typing helps with that.
Is there a precedent of statically typed language displacing duck-typed one? I don’t think so. Golang was supposed to be one such attempt, but it doesn’t seem it comes even remotely close to Python’s popularity. That’s despite Google backing, fast compiler, super-low GC pauses and simplicity of the language. If Google can’t do it, why should we risk wasting time on it?
As for Python being “quick and dirty testing ground”, I was speaking with HFT (high frequency trading) developers and the situation there is that mathematicians are developing their algorithms in Python (which results in slow programs), which are then rewritten into C++/ Java/ etc by proper programmers.