I do not think it is a scam. It is actually something creative of those gurus like you (as you say so) to think about it. Selling guides is not a scam but it is like selling textbooks for school. The only difference is how the learning on those guides or textbooks are put into action.
If the competition is tougher, it is not the guide seller's fault. That is on the part of the buyer to do market research before putting up the business.
interesting points, but its the ones who promise you will make money which is like 80% of them.
Everyone and every company that sells something will tell the prospective buyers that they buyers will gain something good from the merchandise. That is common sense. Have you ever encountered any seller who tells you something bad about his or her products?