Why is uncle's position in traditional China society so high?

The eagle in the sky is bigger than the uncle on the ground. This is the custom of Wu.

As the old saying goes, "There is a thunder Lord in the sky and an uncle in the ground", and the status of an uncle among the people is also above other relatives. Because my uncle belongs to her family, there are relatively few things involving interest disputes between family and relatives, so many contradictions are "my uncle has come to an end." Old uncles seem to have a supreme position among the people ... Now people often call those prestigious and just old people "old uncles".