I really like your comment on this. This is so true of almost everything. It’s a derivative of something that someone else thought of at some point in time. I hate to say there are no new ideas, but for many things this may be the case.
I also understand the OP’s position, but I’ll say this: If I’m making something strictly for my own use, I’m not likely to worry about the morality of it. The reality is, I was not going to buy it from the creator because I have the talent and tools to make it for myself. So the creator did not just loose a sale, I was not a potential customer to begin with. I would not have bought it if they offered it for sale, I enjoy the process of making it and I can do so at my own pace and perhaps even apply my own enhancements.