Respectfully, thats not quite correct. A BOM is just the aggregate costs of the parts of a unit. Engineering,set up, production facilities and machinery etc is factored in the mark up during the FEED (Front End Engineering and Design) and is considered a fixed expense over the life of a product. ( since its usually only done once). Labor, marketing etc is computed in the COGS (Cost of Goods Sold) on the back end and is constantly reviewed and adjusted for market and business considerations as those are usually dynamic.
The parts etc are factually a minor consideration in the cost of a unit because they are usually the cheapest part of the process. Manufacturing facilities lose money and go bankrupt in almost all cases not because of the BOM costs or a unit or a bad market- they go down because of all the losses due to quality problems, rework, ineffective methods, worn out equipment not operating at peak performance and human issues. ( thus the 7 major losses in TPM and six sigma) In the graph of the maintenance or process icebergs- these losses are the "bottom half" of the iceberg than nobody addresses until its usually too late because they are not above the water in plain view. This is why the japanese ( and not other countries) are eating our lunch- they are cheaper and better because their operating effeciencies are well above 90% compared to 40-60 for the average US firm.