What caused 300 years to be the lower limit of China Dynasty's national luck?

From Qin Shihuang's accession to the throne to Puyi's sudden abdication, the feudal dynasty in China experienced more than 2 100 years, with 9 dynasties and more than 50 small dynasties. Among these feudal dynasties, except the Western Han Dynasty and the Eastern Han Dynasty, the Northern Song Dynasty and the Southern Song Dynasty, none of them lasted more than 300 years. What is the reason why 300 years is the lower limit of China Dynasty's national luck?

Since Qin Shihuang reformed the county system, there was only one country in the modern China world where the central government indirectly collected taxes from every farmer. This political system has a strong pioneering ability, and can fully guarantee the tax revenue, which has carried forward the secondary achievements for the stable grasp of the feudal dynasty. However, this principle of centralization also has its limitations.

The modern feudal dynasty has always been on the edge of agricultural society, and the broad masses of Li people depend on harvesting sites for food, which is the most secondary means of production. In modern times, the secondary meaning of wealth is to own a large area of land, so the land will gradually be plundered by foreign dignitaries. This is the problem of land consolidation that is often mentioned in history. After the site merger, the peasant class changed from a yeoman to a tenant farmer, attached to foreign dignitaries and then grew stronger. When the strength of foreign dignitaries develops to a certain extent, they will have their own views on the dynasty regime. Another situation that is likely to break out is that farmers who have lost their land have no capital to survive, and they simply force themselves to rebel and establish armed forces to overthrow the dynasty.

From the central government's point of view, the ability to master foreign countries is gradually weakening, which means that the tax revenue is less, the launching ability is weakened, and it is impossible to cope with the endless projects of war and disaster. Once it's generated, it's there? Probably a traitor invaded, and the dynasty regime was bound to fall apart. The small-scale peasant economy of feudal dynasties always existed, and the rise and fall of dynasties always rotated. 300 years is the lower limit of this cycle.

Now, more and more experts believe that the weather is also the secondary reason why the modern dynasty of China did not last more than 300 years. According to the research, the cold and warm periods of modern weather in China almost broke out in two or three hundred years. During the cold period, crops will increase production and lead to famine. In order to compete for food capital, war was inevitable, which led to the demise of the dynasty.