Nor am I. At least beyond tales of Atlantis and Mu. I’m not willing to totally rule out the possibility, though.
And I’m also assuming that the pyramids really are only 4500 years old.
Still, how much recognizable evidence would there be of a society that was so advanced that everything they built and used was biodegradable and recyclable, after an intervening ice age and major sea level fluctuations?
Keep in mind that so 80% of the world’s population lives within 200 ft of sea level and that sea level rose 300 feet after the last ice age...
The evidence would be enormous.
Such a civilization wouldn't just spring up out of nowhere, going instantly from the Stone Age to 21st Century (at least) technology. It would take thousands of years and a population base of at least hundreds of millions of people. Such a civilization would leave worldwide evidence.
A trivial example: glass bottles, when buried, can last essentially unchanged for hundreds of thousands of years.
Another example: the amount of metal used in a modern city would leave traces in the soil and rock that could still be detected millions of years later. Even if your hypothetical city recycled to an extent that would make environmental activists giddy with joy, they still would have had cities in their past that didn't have the technology to do so.
If there had been a highly technological civilization prior to 10,000 years ago, we would have found traces (and more) of it by now.
I wholeheartedly agree, there would be nothing much to find, and thousands of years for unfamiliar artifacts to be vandalized, melted down, reused in other ways, dumped somewhere else, incorporated into foundations, and of course, more or less permanently obscured by the last rise of the seas after the glaciers melted.