The point of this parable is that neither company has any clue what the actual value of the work done was. Alan looked like he was working hard and was rewarded for looking like he was working hard. Charles looked like he was goofing off and was rewarded for that.
Yet when you compare the results, Alan took 24 programmer-months to solve the problem, and Charles took 3 to do it better. If the companies had some way to objectively value the work done, Charles is clearly vastly better. But they don't.
It's got nothing to do with the specific techniques involved. It doesn't even weigh in on the reason for the difference -- is Charles brilliant compared to Alan's normal, or did Alan just stumble and turn a simple task hard? That's all irrelevant.
The point is just to illuminate how hard it is to know the value of a developer's work. I know I've run into that repeatedly in my career.
That a thing is a parable does not render it immune to disagreement on realism grounds
Indeed if the defense is to point out that it's not meant to be realistic then it's probably not just valueless, but of negative value
Parables are not a good way to learn in my opinion