Coming back to the book. Its fairly unlikely that anyone already in the business would buy it unless it was just to see what it was like.
Once again its the old thing with WFP being offered as a new business proposition to people outside the trade who would NEVER have considered starting up as a trad window cleaner.
I don't know but I'm guessing from the several images of wads of money in the pictures that this is promoting the idea that WFP window cleaning is SOOOO easy and you can make SOOOOO much money etc etc.
This was forseen from early on and the predictions appear to be coming true.