What is the reason why America has become a modern power?

The free economic development model, the integration and utilization of various cultures, and the most important thing is that it is relatively new and has no more historical burdens. Just as Shenzhen in China is developing faster than other established economic centers, there is still an insurmountable gap with Europe and America because of the political system. In China, politics restricts economic development and the system remains unchanged, so it is difficult for China's economy to advance by leaps and bounds.