GDP means nothing if a country doesn't have industrial and tech to defend itself.
In 1900 China's GDP was comparatively higher than what China is now.
"In 1900, China was estimated to have the second-largest economy in the world, trailing only the United States. At the dawn of the 20th century, the U.S. had recently overtaken China as the global economic leader.
In 1900, China’s GDP is estimated to have been roughly $23 billion to $25 billion in historical international dollars, accounting for approximately 11% of the global economy."