It depends on what you mean by 'production'. I've had great success setting up my data collection, engineering and predictions in batch processes. I agree though, I would never try to use R with a REST API, but I don't think it was ever designed for that.
As a general rule of thumb, if something needs real time predictions or I need deep learning libraries, I use Python. R is for anything else.
As a general rule of thumb, if something needs real time predictions or I need deep learning libraries, I use Python. R is for anything else.