Based upon past and present, answer is no. Because usa has strong factors to contribute to their economy. World's largest and biggest companies are found in usa and those companies are ruling the World. Like Apple, Google, Microsoft, Amazon, Facebook. These are top 5 companies who are responsible for their growth in economy and gdp. As you know, GDP is the main factor that plays important role in increasing the revenue share, market value and ofcourse economy. Now take a look at China, China also have lot of big companies like bbk electronic, alibaba, tencent and many other. Sure they are billion dollar companies but not close to usa . As a rivalry, china always try to become superior over usa but the fact is most of the people or workers are from china in USA based companies So in my opinion, considering economy and market value, USA is the leading country. I don't think so china will surpass USA in world's largest economy.