His design might be open to copies. But so does every major company, like Apple for instance. I'm sure the hypothetical inventer would make more money selling units than mining with his invention.
If you see no point in this discussion then don't discuss on it!
Bitcoin is a fixed supply currency so you logic is a little off. The person would make much more just mining themselves because they would only need to support their own operation, not others. There is not point to this discussion because you point counter basic human nature for the most part, people are self-interested and to moderate amounts that is a good thing and is why we see so much progress in the world.
What you want to talk about is utopias that don't exist. You could in fact design a chip that is better than anyone else and sell it to the public but I figure once you started looking what it will take, you may understand better the points being presented. Proof positive is the fact that all chip makers have their own mining operation and mine more than they sell.