In the feudal society of more than two thousand years in ancient times, all the dynasties were inherited by the eldest son, and the emperor would appoint an heir before he died, passing the throne to his next generation. Can't retire early to enjoy life?
In fact, there are many reasons for this, one of which is to prevent the princes from killing each other in order to compete for the throne, because there were many things that competed for the throne in ancient times, so in order to prevent such a situation, there was a situation where the emperor did not retire early.
The second is that the relationship between the Emperor Taishang and the Emperor is not easy to handle, so whether any decision made by the new emperor should be made to ask the Emperor Taishang, and whether not to ask for instructions is not to respect the old emperor.
Therefore, if the old emperor is still alive, then it will cause an invisible pressure on the new emperor, so for the principle that more is better than less, it is generally necessary to wait until the emperor dies and the new emperor takes the throne.
There is also a very straightforward reason is because the temptation of power is too great, the power is in hand, everything is echoed, and if it is not in hand, no one will listen to their own words.