First, thanks OP for giving the community a valuable opportunity to share some valuable insight and shed some light on the "non working methods and scams" aspect of BHW. I think I speak for everyone when I say what we need is the chance to educate some people as to why they are failing so miserably.
Alright, to tackle the first part of your question. The reason most methods aren't workable is that 95% of the people that read a post on a method and try it out have sh*t for brains. The vast majority of people will copy paste the method directly and cause it to become oversaturated. Others will copy paste the method into an ebook and sell an idea that could have made hundreds of people thousands of dollars. Instead, more lazy people are given the chance to further oversaturate the method. But, there is a small, glimmering piece of hope here. Maybe, just maybe, one day people will learn to use their brains (assuming they are able to find them) and actually put their own twist on a method and make it work for them in their own context and not cause oversaturation. (Do not hold your breath, suggest buying A LOT of compressed oxygen)
And to adress the second part of your question, the term scam is rather harsh and depends entirely on point of view. Instead of scam, we should be considering these works of art to be an "simplified wealth redistribution system". To rephrase this, these so-called "scams" often involve targeting people of lesser intelligence and relieving them of money that they will more than likely squander on porn or cheap decals for their poorly modified import cars(also referred to as douchewagons). Instead of this money being squandered and put in to the pockets of unscrupulous businessmen preying on these poor misguided morons, we should be using the invisible hand of black hattery to guide these people to doing the proper thing and investing in us so that we may better ourselves and humankind. We can also think of this as natural selection, or survival of the fittest, if you will. That being said, if you feel that you are taking advantage of someone then always remember, someone will be taking these fools' money, so why shouldn't it be going to something other than douchewagons and porn?
Thanks.