> I'm guessing that's not in the web dev field but rather in the data analysis field.
I believe this is correct. Python is not likely growing in app development, but for data analysis and related backend tasks - in the same areas R is seeing a popularity boost.
It is, but does not need to be destructively so. Become an expert in a few, and competent in several (over time). If app dev is your thing, with Ruby/Rails and JS you probably can't go wrong. Pick up some PHP for when you (will) encounter it.
I believe this is correct. Python is not likely growing in app development, but for data analysis and related backend tasks - in the same areas R is seeing a popularity boost.