To answer your question it is best to look back at the history of the automobile. The automobile or horseless carriage has a history stemming back to the 1300’s. There are many accounts in Europe of people investigating and attempting to build what we know today to be a car.
The idea gained popularity in America in the later 19th century. The early inventors and entrepreneurs started to build cars in their barns. They worked on these until they developed a good product. As the car became more and more efficient the production picked up and entrepreneurs started to buy larger buildings and hire people to help them build their cars. They advertised the cars by having races. One of the most famous cars to race was Henry Fords 999.
The production of cars is the key to your question. While many think that Henry Ford was the inventor of the car, the truth is he was the inventor of the assembly line. When Ford put into practice the assembly line cars became cheaper and more affordable for the average man. Before this only the rich could afford a car. So car production, using the assembly line, became very popular. As the years went on there were several things that happened between companies, owners selling out, etc. but the assembly line never left.
By the 1950’s cars were being mass-produced using better, more advanced techniques of the assembly line. The 1950’s also had some issues with workers. There were Unions in place by this time to help the worker gain some voice over their job, working conditions, hours worked, and pay. During the 1950’s there was a good demand for the car. People had grown to rely on it. Women started to drive and they wanted colors on cars that had not been there before. Production changed because the demand changed. Whenever demand changes then the supply will change. The bottom line is the assembly line is still in place today, making production efficient, yet as time goes on we see that the operation of the assembly line is becoming more and more automated. So there lies a new set of problems. The worker is not as valuable as he once was; now we have machines doing much of the work in assembling cars.