They don't know about Seth saying:
'There were fully developed men — that is, of full intellect, emotion, and will — living at the same time, in your terms, as those creatures supposed to be man's evolutionary ancestors. Species have come and gone of which you have no knowledge. There are parallel developments. That is, there were "apes" who attained their own "civilizations," for example. They used tools. They were not men-to-be, nor did they evolve into men.'
—Seth, The Nature of the Psyche, Chapter 11, Session 796, March 7, 1977
https://apnews.com/article/early-humans-oldest-structure-zambia-wood-de6350a2c9704477a2df4e0a5ba8d311
I was reading about proto humans Mark and tools found 3 million years old and I was thinking how can scientists really be serious in thinking nothing happened between then and now..