- I work with several people who are purely data scientists, and I lean on "culture" rather than "Jupyter". In some circles, probably influenced by academia, programming is considered to be low status work. You are not going to solve the problem by switching to .py files, even though for most tasks literally anything is better than Jupyter.
That they don't use git, or that git wasn't originally even a concern, is a consequence of that low-status perception. If you pitched something to the developer community and told them "oh, by the way, you can't use git", they'd synthesize tomatoes out of thin air to throw at you.
- I'd carve an exception for stuff that satisfies ALL of the following: (a) is self-contained in a single notebook, (b) has no dependencies on anything non-standard, (c) is demonstrative in nature, or a personal exercise rather than production software. For example, I wrote my solutions to the Advent of Code problems in a notebook and I liked the experience, especially how you could mix math and code.