There is no hard and fast rule about the techniques or strategies being taught in these products. That's what they are... techniques/strategies. You have to test different models to see which one works the best for you.
The exact same website functions, OTO's or products aren't necessarily going to work for you in the same manner they worked for someone else and that's because everyone thinks differently when constructing the offer, naming their product, marketing strategies they use, sales copy they create, etc.
So to base your entire model off of someone else and expecting the same or similar results is ludicrous...
Training materials, books, videos and home study courses are designed to give you the information but you still have to think on your own, make your own decisions and it's those decisions that can make or break you.
That's why it's more important to understand the concept of these strategies and then thinking how YOU can use them in your business.
That's the biggest thing everyone misses when buying a course. They figure if they buy the course and follow it verbatim they will get the results. What you need to do is understand WHY marketers do what they do and when and on which offers.
PS. So the next time you buy a course or an ebook and read it, then complain it's a SCAM or doesn't work, you should ask yourself "Do I really understand the concept being taught here?" before throwing it to the side.