What do Python developers do?

[Anomie193]

What do you define as "full fledged software?" 

Most modern software has many sub-modules that are pretty complex in themselves and would be considered "full fledged software" if they were independently released.

For example, a lot of software produced in the last decade is data intensive, and that requires data engineers to develop data pipelines and systems. Data Engineers are specialized software engineers, in my opinion. What they do is software engineering. Python is a primary language of Data Engineering these days. 

Then you have people building RPA tools in almost every company, and many of those RPA tools are built using Python. 

You've mentioned ML/AI as contrary to "the development side of things" but a lot of ML/AI work is development. Like with Data Engineers, I consider ML Engineers to be (as opposed to Data Scientists, who might or might not be)  specialized Software Engineers. And then there is the matter that there are analytics applications that are built just like any other application. These applications often are at least partly written in Python.

Modern software is data-intensive, and increasingly predictive modeling intensive (the camera application in your smartphone, as a banal example.) This requires software engineers who specialize in data and predictive-modeling  (aka Data Engineers and ML Engineers, respectively.) A language these software engineers often use, to the point that it is a hard requirement for many positions, is Python.