Being able to pick a time-tested, reliable package that you can suspect will be maintained the next few years forward has incredibly value. The NPM ecosystem does not provide it.
I can point to a full suite of data science projects in npm with varying lifespans from 1-3 years. Given the null assumption (it will be maintained about as long as it has been maintained so far), this seems to meet your requirement?
That NPM has churn is an example of how massive that ecosystem is compared to PIP, which is comparatively microscopic and is much more dependent on specific corporate actors to continue investing.
What data science project in NPM are people actually using? There are literally thousands of people using NumPy/SciPy + Matplotlib. NumPy, BTW, is over 10 years old and counting.
Javascript is a terrible to do data analysis, given its inferior numeric data types.
