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.
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.