What are the reasons for the breakthrough in the economic development of the United States in the early 20th century?

The market economy that developed in the early 20th century in the United States was driven by previous experience. Various branches of industry and agriculture developed fruitfully in the country. This was due to the absence of class restrictions and an increase in the rate of production. In the United States lived people from different countries of Europe and Asia. They developed mining activities on the mainland, because there were a lot of minerals and natural resources that served as material for production.