The cost of materials in a folding knife, including the blade steel, can vary based on a range of factors, such as the manufacturer, the specific steel used, the production volume, and other associated costs.
Typically, the price of the steel itself in a good quality folding knife like S90V or M390 might not be a significant portion of the total cost. Other components, such as the handle material, hardware, design, labor, marketing, and distribution, can play a more substantial role in determining the overall price.
It's important to note that the steel choice is a crucial factor in determining the knife's performance, durability, and edge retention, which can influence its overall quality and price.
If you are interested in finding out the current percentage of steel cost in a particular knife model, I would recommend checking with the manufacturer or reputable knife retailers for the most up-to-date information. Prices and cost breakdowns can fluctuate over time due to various market factors.