I'm really interested in the answers to those questions, because I have experience working in Python and JS shops and I haven't noticed much of a difference in

I'm really interested in the answers to those questions, because I have experience working in Python and JS shops and I haven't noticed much of a difference in terms of engineering quality between the groups. I suspect it's because most JS and Python engineers lack experience working with "non-magical" languages, and thus they frequently lack the ability to make good performance estimates or balance competing priorities. Or maybe the non-magical thing is a red herring, and it just happens that non-magical languages tend to be employed in domains where "just make it work; we'll solve performance with hardware" isn't acceptable. This isn't to hate on Python or JS engineers; just that I don't see the same jump from JS to Python/Ruby that I see in dynamic to static languages (esp static langs with manual memory management).