Why would division of labor without trade not work?

Division of Labor:

Division of labor is an economic idea and practice in which the production process is segmented so that each worker performs certain jobs that they are best at. A single worker or a group of workers performs a specific task.

The division of labour refers to the division of a manufacturing procedure into a number of tasks, each of which is performed by a distinct person. Instead of one person doing all the job, the labour is split among the workers. Because of three fundamental reasons, division of labor leads to specialization, which leads to improved production. To begin with, specialization leads to a comparative advantage, which means that each worker concentrates on the activity of production where they have an edge over others. Second, specialization boosts both the quality and quantity of items produced. Third, specialization allows a company to benefit from economies of scale, which means that as the volume of production increases, the average cost of production per unit lowers and the company's profit rises.