Why are the writing contents and calligraphy styles of Chu bamboo slips and Qin bamboo slips so different?

Chu belongs to the pre-Qin period. This fashion is that when there are many vassal States and the cultures of different countries are quite different, the characters of each country also have their own unique styles. After Qin unified the six countries, it re-created its own fonts, resulting in the official script and seal script of Qin, and the mainstream script is seal script. Then the development of bamboo slips is based on the inheritance of predecessors, and the writing of seal script and official script is parallel. The speed of writing also directly leads to the difference and differentiation of styles.