What are the factors of placement of mechanical engineering. What is the leading factor?

Mechanical engineering is an industry that primarily requires a large number of skilled workers. Depending on the mechanical engineering industry, either working specialties of secondary and primary vocational education (locksmiths, turners) or higher education (precision and nuclear engineering) are required. Therefore, engineering plants are located primarily in large cities where there is an educational base, as well as the population. It is better if the plant is located in the region where the sales are made. But this is not a critical condition.