The study looks at how companies decide to either make all their products in-house (vertical integration) or buy from others (outsourcing). The researchers found that in a model developed by others, no industry had both types of firms. They built on this model by adding that companies need different goods apart from labor to make their products. In their new version, they discovered that there can be a mix of integrated and specialized firms coexisting in a balanced way. So, in real-world industries, there can be companies doing everything themselves and others focusing on specific tasks, both succeeding side by side.