There's a trade-off between specialization and vertical integration (doing everything in house). By specializing in just one thing (e.g. making shoes), and let

There's a trade-off between specialization and vertical integration (doing everything in house). By specializing in just one thing (e.g. making shoes), and letting someone else package them, transport them, market them, help customers try them on a store, etc., you can get really damn good at just making shoes. The shoes you make will almost assuredly be cheaper and of higher quality than the guy that tries to do all the other stuff himself (in addition to making shoes). In America, for physical goods, specialization almost always wins out despite the profit taking at each step, because labor is so much cheaper in other nations. Tesla and Trader Joe's wine are two great counter examples of vertical integration winning out big in industries that had become over-specialized over time.