Cutfingers:
There are a variety of makers of this type of diamond water stone -- a quick search turns up Naniwa and also the I-Wood versions. If you're interested, perhaps you can order those and thereby know who makes the ones you get.
From my perspective, the only real reason to know who makes Jon's is to try to do an end-run around him and find them from a less expensive source, or for someone else to source them and start selling them. I can understand Jon's reluctance to share the maker, for these reasons if no other. We also don't know what the manufacturer has told him about sharing their name. Further, it may be the case that his product is in fact unique, due to his input during development and an exclusive right to the product developed therefrom; if so, sharing the maker's name will have little or any value.
At the end of the day, if you are going to consider this set, you need to rely on Jon's word, reputation, and experience, plus the feedback of others. Jon has invested his time, money, and expertise in locating, testing, and importing these stones (and perhaps also in developing them). Seems to me he is entitled to tell us what he chooses to with regard to their manufacturer. Do I wish they were less expensive? Sure. Would I love to be able to buy them from someone else for a lower price? Yes. Do I hope he is taking what I would consider a fair markup for his efforts? Yes. However, I also think he deserves to be compensated for his efforts.
One reality of the internet age is that it is easy to find multiple sources for products. Too many people go to a bricks and mortar store to test out something (electronics, clothing, books), then go online and order from the cheapest vendor. That is fundamentally unfair and unethical behavior, as they are relying on the investment of the bricks and mortar store to test things out, but not compensating the store for that investment.
Finally, for you to analogize this to a chef and his ingredients is not fair; the food you get at a restaurant is not just a function of what the ingredients are, it is result of the ratio of the ingredients (i.e the recipe) and the preparation of same. If Thomas Keller tells you the exact ingredients for a dish, does that mean you can replicate it exactly? I don't think so. So, his sharing the source of his ingredients does not substantially weaken the value he delivers nor the price he can charge.
However, if Thomas Keller has spent his time and energy identifying what he believes is the finest olive oil, and he imports it and puts his name on it, should you expect him to tell you from whom he sources it?
Here is the ingredient list for Jon's stones: aluminum base, diamond, ceramic, coloring agent. Now, you or anyone else can replicate the stones.
