Why would china have been far more likely than european nations to become a colonial power up until 1433?"?

During the time of the Tang Dynasty in the 600's AD China could have become a major colonizer of western hemisphere due to their strong hold on ship building and navigational technologies. They had a huge manpower and all the resources, still they chose to not colonize the world. By 1400's China had tremendous maritime technologies and had enormous fleets at hand for their several voyage expeditions that took place till 1433, but they did not colonize the world as it was against the nature of the historical Chinese states to not explore, to not colonize or to not expand outside its sphere of influence in East Asia.