If you wanna understand this question a gotta look up the Chinese and European Opium War but I'll give my short answer to this.
Back during the Qing Dynasty, China was the zenith of economic leadership. They were prosperous in literally every single area of trade all across the globe. Because of this, the Qing emperor, Qianlong, knew China had no reason to seek better trade deals or go on ventures in expansionism. When the Europeans came to China to ask for basically spheres of influence and a piece of land to start more trade with China (the land with everything) which would only benefit the European opium, Qianlong was like "hell naw". Europe was like "bruh" and is still salty about it today. Qianlong was just stating the economic situation at the time and in reaction to it he rejected the european trade requests cuz china had everything and he knew europe couldnt complain cuz they dont control a ton of the resources at that time.