Good idea, wrong metric. What should fit in a screen is the concept. If you take a big, hairy, complicated thing and just chop it into several functions that fit on a screen you have gained nothing.
Now the reason I posted that inlining article from Carmack leans heavily into this line of advice: "if a function is only called from a single place, consider inlining it."
Taking a complicated mess and breaking it into functions that are called from a single place seems better served by organising the code (maybe with duplication if needed) and writing inline comments rather than devoting a call tree to that section of code.