Um, fellows...
tamahagane, sushi knife, sushimen, sushi cutting knives, deba, kazari, yasi, japenese, japanese, master, chef, yanagi, tachi, case, cutlery, martin yan, yan can cook, knife, lifetime warranty, sale, lowest price, set, serrated, bread, ironwood handle
and...
The Japanese Knife Company - KNIVES - LAMINATED STEEL - TAMAHAGANE
If this is an example of the kind of steel you speak of, then we need to review a common problem that has been discussed here as to labels that appear on razors. It's a marketing thing, not the steel.
If Iwasaki or others have been licensed swordsmiths there is no question in my mind about the legitimacy of their access to tamahagane. I would not question metallurgical researchers or even well respected good friends of swordsmiths or the master smelter himself Kihara-san. I have samples from both kinds of friend. There really should be an unusual or uncommon reason for that steel being distributed outside the very well controlled chain. This does not mean that lesser quality product from the tatara could not be available. I cannot imagine that the "good stuff" would be lost somewhere.
This does not mean that a toolsmith is prevented from building his own smelter and rightfully making his own steel. That material would also be tamahagane and would not be controlled through the present set of regulations. It would not be official, but if of good quality, it would be respected for what it was rather than looked upon as automatically inferior because of it's manufacturer.