I agree with your conclusion. The easy part, if it can be easy, is doing the writing. The hard part involves creating a demand for your finished product. I have learned much from other authors about marketing and suggestions through networking sites such as this and newsletters that I receive. In today's market there is ample opportunity to market your product. The key is to establish how it is different from those already published. This will create a demand for it with marketing perspectives that keep developing as people create new methods and new opportunities to market and gain exposure for your talent and expertise.