I was taught about the benefit of trade in my first economics lesson. People from place A and place B want apples and oranges and they both grow apples and oranges
themselves respectively. They provide themselves with apples and oranges. However, if people from place A focus on growing apples and people from place B focus on
growing oranges, then they exchange apples with oranges, people from both places will benefit more. If people from place A only grow apples, they will
develop better skills in producing apples. Besides, the climate and the soil of place A could be better for apple to grow. If people from place B only grow oranges, they will
develop better skills in producing oranges. And the climate and the soil of place B could be better for orange to grow. The yield of apples and oranges from both places will
be higher comparing to people from both places producing apples and oranges themselves. If people from place A trade their apples for oranges with people
of place B, people of both places will benefit more.
It is the benefit of specialization, economy of scale and trade.
Economics is not science. It is social science. Not all the theories of economics are agreed by all. However, specialization, economy of scale and trade are agreed by most of people.
People have a lot of expectation with new inventions. A lot of people expected 3D printing would be a new revolution in industrial production.
However, applications of 3D printing is still very limited after more than ten years. 3D printing is used in prototype production and some special products with limited quantities.
Applications fo 3D printing is limited because it violates the benefits of specialization, economy of scale and trade. One has to do the design, purchasing of materials
and production himself. It violates one of the most accepted economics theories.
What kinds of new inventions will follow the footstep of 3D printing. We will see.