Time and our dynamic earth have buried more than we will ever know.
Then, a lot of what has been buried is later consumed, over long periods of time, in the plate tectonics, as the edge of some plate is submerged below another plate and what remains on it is crushed to extinction by the heat and pressures below the surface.
Who knows but what we call the ancient past today is not actually young compared to some period we will never seee the evidence of.
Yep, that is a fact. :)