I watch a lot of Youtube videos. My most recent being the Etruscans, the Minoans, and now some on the Incas. We don't have cable. We use a Roku with the internet. We do have Netflix, and Amazon Prime, but...I watch a lot of Youtube videos. 
I have in intense interest in the megalithic builders. Which, IMO, were NONE of the "modern" cultures, including the Egyptians. I have stood on top of The Great Pyramid, as well as inside. I agree with you about that.
I have no trouble believing in eons upon eons . . . and advanced civilizations in untold eons earlier on the earth. I've long speculated that such was the case.
We are not told what the earth was BEFORE it was "formless and void" in the first part of Genesis.
God seems to be intent on training, refining, teaching, etc. individuals to rule and reign with Christ over countless galaxies and eons.
It's quite plausible that if that's His main priority, He might allow civilizations to advance to a certain point and then mush it all over; remove all evidence of such and start over with a low level of agricultural social structure.
The priority is evidently to
TEACH LOVE and HUMILITY.
That mostly requires RELATIONSHIPS where people need one another.
A basic agricultural level of technology is quite sufficient for that.
Higher levels of technology seem to go hand in hand with greater levels of evil and destruction of fellowman.