I my opinion, a big chunk of "data science" work is also the collection of data and eventually some sort of deployment. R is great, but in my opinion, it is functionally a little bit limited to the middle part: The statistical analyses and predictive modeling/machine learning.
If you need to use/build a data scraper or want think about developing e.g., an online app for your classifier, you are way better off with Python. I am saying this as a former R guy who made the switch a couple of years ago...
