The Yuan Dynasty and the Mongol Empire were two different things. Although the Yuan Dynasty was still nominally the suzerainty of the Mongol Empire and the suzerainty of the various khanates, from the death of Genghis Khan, the Mongol Empire had actually split, and the khanates were on their own and did not fully obey the orders of the central Yuan dynasty.
Moreover, because of the uncertainty of the Mongol succession system, wars between heirs often occurred. After Kublai Khan succeeded to the throne, he fought a long war with Ali Buge. At that time, from the traditional habits of Mongolia, the legitimacy of Ali Bu Brother was stronger than that of Kublai Khan, so most Of the Mongol princes chose to support Ali Bu Brother. After this war, the Yuan Dynasty and most of the Mongol Khans in the west and north were in a state of opposition.
From this point of view, although the Mongols did conquer a large area, and most of Eurasia was conquered by the Mongol Empire, this was not all a territory that the Yuan Dynasty could effectively manage.
Even in terms of the areas that the Yuan Dynasty could actually control, if you only look at it from the map, the Ming Dynasty is indeed smaller than the Yuan Dynasty. But conversely, the Ming Dynasty's actual control over its own territory far exceeded that of the Yuan Dynasty.
The Yuan Dynasty actually did not talk about any governance at the local level, let alone any effective governance, the entire state management was very simple and rude, as long as it did not delay fiscal revenue, how simple the governance came, mainly relying on force to suppress. So now some people say that the national legal environment was relatively relaxed during the Yuan Dynasty, in fact, it was not loose at all, but lazy, too complicated, they themselves could not play, and they did not want to rely too much on the Han people, and could only try to be as simple as possible.
Therefore, the actual control of the Yuan Dynasty over the localities was not strong, and the stability of the entire state's rule was particularly poor. In just one hundred years, the whole country fell apart under the impact of the peasant uprising, and the local government was completely incapable of effective control and suppression, and could only sit back and watch the peasant uprising sweep through the country and finally be overthrown.
The Ming Dynasty was completely different from the Yuan Dynasty. The Ming Dynasty also carried out external expansion in the early days, but the main purpose was to combat the remnants of the Yuan Dynasty, that is, the remnants of the Northern Yuan, as opposing regimes. The Ming Dynasty was essentially a country based on agrarian civilization, so it paid more attention to practical and effective management and control, rather than blindly staking land and laboring the people and hurting their wealth.
For example, for the Xinjiang region, which was already Islamized at that time, the Ming Dynasty did not carry out a large-scale military conquest operation, but stopped after arriving at Jiayuguan. Although the expansion of the Ming Dynasty to the west and north was not positive, on the contrary, it had a more negative attitude, but only drew the land and defended itself, and gradually formed the actual control territory bounded by the Great Wall.
But at the same time, the Ming Dynasty strengthened its control over the southwest by constantly suppressing various ethnic minority forces in the southwest that were obstructing the dangers of the mountains. Although the southwest region has been included in the ruling territory of successive dynasties as early as the Han Dynasty, the actual control ability is not strong, so there will be a situation in the Tang Dynasty such as Nanzhao and Dali in the Song Dynasty, and the situation of the imperial court competing with each other. In the Ming Dynasty, through continuous military action, these areas were gradually brought into the actual and effective control of the imperial court.