Why? That would create lots of small functions that each is called only once from only one place in the code and still are extremely coupled to the invoking switch statement, often having multiple inputs and multiple outputs which then the invoking statement needs to write in the proper places to which the function wouldn't have access.
Breaking out functions makes sense when you get either reuse or decoupling, but in this case you don't get any of these.
Because it would objectively and shockingly obviously make the code easier to understand.
You would be able to see what it does at a high level at a glance and then drill down into the functions and sub-functions to focus on a particular part of it.
With this version, to get the high level overview you have to scroll through multiple pages of code and find the comments that say what each section does.
So the problem is being able to drill down? Most decent IDEs allow you to collapse code blocks (i.e brackets) if that's what you want to do, and the comments accomplish the same thing a function name would. Some editors support region comments that start out collapsed and can be named. I don't see why separate functions would be anyones first instinct to reach for here.
Breaking out functions makes sense when you get either reuse or decoupling, but in this case you don't get any of these.