I think perhaps, everyone is missing JB's point. He is not saying (I hope) that there was no human activity on the earth long before the supposed creation date of Adam (according to WT) in 4026... I thought he was just saying that before writing came about, and actually quite a bit of time after that, there was no concept of creating a historical record of anything. The concept of creating a written, historical record of past events was actually a much later event. Most of early writing attempts are not at all attempts to provide a historical record.
A good question is actually: who was the first historian?