Because of freedom of the internet one doesn't need an ad for sales it is used to drive in traffic on the link or directly. Ad's stimulate, think of it like a commercial. No cash from my ad's either, you are not alone.
Well, everything is about a luck, I also don't have any Amazon sale, but you need to be patient.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.