I have several patents, and have consulted with some very expensive patent attorneys. I am not going to give legal advice. I do know the difference between a design patent and a method patent. A design patent is relatively easy to get. It is intended to cover the design appearance and unique details of a product (think about the decorative brace on a saxophone between the bell and the body tube). That patent is quite specific to that product type.
The method patent is supposed to be a unique innovation. A new idea. I have been told that both prior art and obviousness will prevent examiners from granting a method patent. As others have pointed out, you may have a basic new idea, and another entity can incorporate your idea with a wrinkle, obtaining a new patent. That is like person 1 inventing a pencil, and person 2 adding an eraser. Neither can sell a pencil with eraser without infringing on the other patent. However, the litigation can be quite expensive, so wealthy entities can intimidate poor entities.