I don't have a blog yet, but one of these days I'll start. And I have every intention of "giving away" how to do some of my products. Hey, before I was retired I was always interested in the "how to." But if I needed a gift or even something for myself, most of the time I just didn't have time to make the items I might be reading and dreaming about doing, so I bought them. I expect that others reading my (future) blog would likely be in the same situation. While one is still working, let's face it, many people's time to do all these things is limited.
Also, I expect that my tutorials on the types of things I make would be geared to the beginner or intermediate stitcher. I expect that I'll have similar designs but including more advanced techniques in my shop. So again, I expect there will be enough people who would prefer the more complex designs that I'd still get a boost in sales from it in spite of the number who might choose to follow my instructions and make their own more simple design.