Why don't many people understand the Book of Changes, River Map and Luo Shu?

I think I can't understand these books now because they should have been handed down from some prehistoric civilizations, and they contain more mysteries of heaven and earth, so no one can understand them. Moreover, five lines of gossip, which is rich in China, is said to have been realized by Fuxi from the river map, which is also an explanation of the river map. Therefore, we can't interpret it too much now.

Why do I say that these three books may have been left by prehistoric civilization, because there may have been a civilization before Shanhaijing. Now we know that the prehistoric flood did exist and its scope should be spread all over the world, because it is recorded in both Greek mythology and the Bible, plus our own civilization. Of course, this is also a guess, for reference only.

Our Chinese civilization was rebuilt on the ruins after the flood, and most of our myths and legends were handed down before the flood. After Dayu's flood control, other legends rarely spread. The river map is a legend. A dragon horse emerged from the Yellow River and was dedicated to Fuxi, who relied on it to create gossip.

Luo Shu, according to legend, appeared in the Da Yu Luo River. This book was dedicated to Dayu, who successfully controlled the flood with it. The Book of Changes is even more wonderful. It includes three categories: Lianshan, Guizang and Zhouyi, all of which are wonderful books used by Xia, Shang and Zhou dynasties to interpret and pay homage to each other.

The reason why we can understand these books may be because there is a cultural gap between us and them, because it is said that in Fuxi period, there were tens of thousands of hexagrams in gossip, but until Liu Bowen period, he could only recognize 72 hexagrams, and now we can only understand 16 hexagrams.