How is mythology presented as something that never changes in the novel, The Morning of the Gods?

Mythology, a key element of the plot, is also tied to the concept that nothing ever changes.... that the ancients remain where they are whatever happens, and that they never disappear from earth. Even if the shepherd trades in his wooden pipe for a transistor radio on his way up the hill minding his sheep, he shall always remain on that hill and he is still listening to music, whatever its form of creation.