But what about beyond these domains? I'm interested in hearing from practitioners about any production usage across the industry.
Opensource + enterprise parts are all in Python + JS + PostgreSQL. Soon 6k employees.
https://www.python.org/about/success/
One example not mentioned in the above page is reddit which is written in python. I once helped maintain the ANUGA system, mostly python, which was being used to simulate the effects of tsunamis on a shoreline. It can be used for a lot of other things such as riverine flooding:
There are some gotchas to be wary of, and obviously running costs are higher than some other languages/runtimes, but the lower cost of project iteration and development still makes it worthwhile.
OTOH, because of the reputation of being easy to pick up, and thus tons of people murking around with it, you'll get all sorts of crappy code and developers with many years with Python, but no real experience writing production quality code.
All of those are checked in interviews, but can also be learned on the job if there are sufficiently experienced Python developers.
A clear give-away is if someone says they are doing scripting in Python (that usually means no testing, no CI or CD, no code style checkers, no typing...).
Beyond that, I believe Python is also used to program backends but it is not as popular as other BE languages.