Why is tamahagane steel so expensive?

Can you explain why tamahagane steel is considered to be such a high-end and expensive material? What factors contribute to its unique properties and why does it command such a premium in the market? Are there any specific processes or techniques used in its production that drive up the cost, or is it simply due to its rarity and desirability among collectors and artisans? Understanding the reasoning behind the expense of tamahagane steel would be greatly appreciated.