I’ve really only seen python used in academics and data processing.

In the almost 4 years I spent doing security for startups, Python was overwhelmingly the most popular language, not just among clients but among every startup we talked to. That's not counting data science teams.

(I'm not really a Python fan, for what it's worth.)

My recent experiences with startup consulting have involved a lot more new node projects than new python ones. Though I also lump those three languages together as all doing mostly the same thing.

They are close contestant for sure, but don't underestimate the popularity of Javascript among developers: https://madnight.github.io/githut/#/pull_requests/2020/2

There are more niches, industries, and developer cultures than any one of us can fathom.