You can make general statements about knowing the cost of production but you probably do not know the cost of overhead, shipping and mark up. If you think you are paying too much you may be buying a product from a union shop in what is known as a "high cost region". The northeast and the west coast of the US are both known as high cost regions. You will note the high prices from Redding may have something to do with the labor market in New York.
Want something cheap? You can get it cheap. That does not mean the engineering is any good. The cost of the engineering only appears in the overhead. It is not part of the cost of raw material or cost of touch labor.
There is a direct connection between cost of manufacturing and retail cost and you have to factor in the lot size.
You can get a good deal on anyone's 30-30 dies but you cannot get a good deal on .505 Gibbs because they are not built in large quantity. It is no more expensive to make a set of 505 Gibbs dies from the cost or material or labor stand point. The cost of setting up for a new run of dies gets allocated over a smaller lot size of dies and drives the cost up. Modern shops organized to minimize set up labor can produce smaller lots at better prices while maintaining their profit level.
Even though the die companies organize dies into groups for purposes of pricing they undoubtedly do not make exactly the same profit on every set of dies. Many manufacturers sell products that serve to fill out their product lines to keep customers from going to another brand. These line fillers don't always make money.
I am sure they make money on 45-70 dies and make next to nothing on .416 Remington or .416 Rigby dies. It is all about volume versus the cost of set up.