Question about p.44 in "How To Reassess your Chess, 4th Edition"

In "How To Reassess Your Chess, 4th edition", in the chapter on minor pieces and in the section about knights, Jeremy Silman gives the following diagram:

Now, before I kept on reading, I tried to identify the imbalances that involved the minor pieces and tried to work out a plan based on that.  I quickly saw that a) my bad bishop was attacking his good bishop, and b) f5 would be a nice home for one of my knights if I could get his knight to move somewhere else.

Silman notes that the f4 and f5 squares are indeed nice homes for knights, but then goes ahead and builds an Alekhine Gun on the b-file.  Does anyone understand the point of this example if there's an imbalance on the topic of the chapter, but we don't try to do anything about it?

Mate, I think that book is too advanced for your (our) level. 

-kenpo-: oops, you're right, I did.  Here's the sequence:

The file is the most important imbalance in the position. If you cannot understand this after Silman's examples, I suggest starting with "The Amateur's Mind."

This is why I started this thread; what is this example doing in the "Minor pieces" chapter?  If you'd asked me what was the most important imbalance, I would've looked at them all, and I might have figured out that the b-file was where the action was supposed to be happening.  But in a section of the book dedicated to the imbalances concerning knights, I found it very odd that the author would point out that there's a hole where your knight could go, and then work with a completely different imbalance that has not yet been covered in detail.  To me, that looks like a bad example for the section of the book.

Vecht: thank you for taking the time to post that lengthy and informative reply!  Perhaps the point of the example was indeed to show that white can't put his knight where he wants to and therefore, he needs to act elsewhere to kick the black knight away.