> eventually you hit a wall and have to keep investing larger and larger amounts of people or computing resources to get continued returns.

That's certainly my impression. I'm not a professional Python programmer, though I have used it in a few projects that went to prod. I really want to like Python, and it is really nice for some quick one-offs. However, in my project, where the codebase was 30-40% Python, I estimate that 80-90% of bugs and time spent were in Python. The other side of things was more or less write once, never revisit.