The code written by a couple of "data scientists" I was working with is the worst code I have ever seen. They don't care, they just want to have an experimental results. The problem starts when their experimental "code" needs to be used on production or they are asked to describe how it works. Why cannot we just get good programmers and train them as data scientists?
For the same reason we can't just get good programmers and train then in biology or chemistry or structural engineering. Sure they exist, as do data scientists that are really good programmers, it's just that they're more rare and in very high demand.
Often much easier to find a domain expert and a programmer and have the programmer rework the code done by the domain expert. In fact that used to be my job for a while (working with physicists), and it was actually quite fun.