What a romantic idea imagining a speaker builder starting his day tending to the trees in his forest that will someday be used for his cabinetry and trees that will be ground into pulp to form his speaker cones. Then he tours his foundry that is smelting his copper and aluminum and checks on his wire drawing machines to insure all is running smoothly and that he will have enough copper wire to form the coils needed for speakers that day. Next he checks on his capacitor winding machines and the winder making his resistors. But before he can have his morning coffee he must stop by the chemical department and check on supplies of lacquer and solder being cooked up.
That scenario is not very realistic these days due to specialization and economies of scale. R&D costs, tooling costs and just getting materials at a competitive price has driven the world down to a handful of manufacturers for just about every commodity out there. Flat screen panels, for example are made by just one or two manufacturers globally. Even auto manufacturers these days just assemble cars. All of the parts, even the software in many cases is outsourced. Every car shares many common parts from the handful of auto suppliers globally. Henry Ford designed the River Rouge Plant in Detroit to be fully vertically integrated in the early 20th century. It even had its own power station. Those days are long gone.
I have been in and worked in plants that were vertically integrated to various degrees. Some were almost sand and gravel coming in one end of the building and finished product out the other end. It is impressive but typically designed for a single product. Manufacturers will not vertically integrate manufacturing without good reason. They are either forced into it because they cannot find someone to make it for them or they have a secret sauce that they do not want to share with their competitors.
Speaker building is art and science. A speaker is more than the sum of its drivers. Integrating the drivers into a cabinet and matching up a crossover network requires some solid engineering design work, understanding of music, dedication and patience. Outsourcing vs making components is ultimately a business decision. A high end hifi company can't afford to do everything. An engineer that knows how to wind capacitors will likely not know much about machining wood or metal. An electrical engineer designing crossovers is not likely to be a highly skilled cabinet maker. Every employee adds burden to the cost of making a product which impacts ROI- return on investment. If an owner can make more money putting his cash in bonds then he will shut down the business. The market and perception of the product determines the selling price. The cost to manufacture a product has little influence on the selling price. We pay $100k for some speakers because we want to. Ever notice how luxury items have increased in price at or above inflation for decades? Yet the cost of televisions, refrigerators, all appliances are cheaper than ever. Ever notice how willing we are to pay $1200 for a telephone? And Apple has about $56 billion in cash. Cost isn't driving the price.