I don't know. I am not totally sure of course, but there are rather significant examples where it was discovered that past civilizations were far more advanced

I don't know. I am not totally sure of course, but there are rather significant examples where it was discovered that past civilizations were far more advanced than they were given credit for based on the scraps that were the most obvious evidence and remains. I am sure that certain events like invading hordes and economic / ecological collapses have destroyed way more than humanity has achieved. 5 steps forward 4 steps back. Jut take the invasion of the Americas as a rather perfect example, it is now seen as a type of progress, but all the skill, knowledge, and capacity of the Mesoamerican cultures was totally and utterly vanquished and had to essentially be restarted by the people that came to the Americas. Who knows what all was lost. Just imagine what all was lost when the Library of Alexandria burned, I believe that single event set back humanity at least 1,000 years if not more considering opportunity cost and compounding advances. Imagine if humanity had discovered electricity and computation 1,000 years ago.