Actually correct. We have very very few fossils compared to the millions of species that have evolved and gone extinct over 4 billion years.

The fossils we do have are of highly successful species in that geography. It’s a matter of chance, leaving behind a fossil, after all.

And unlike biological matter that can fossilize, industrial structures etc do not. All our manufactured stuff has very short life once it reaches the crust and starts getting compacted.

The more time you add, the better the odds we’d find this evidence lost.

And if this wasn’t a global, but more localized pre-human civilization, the evidence would be thinner still.

Which is why this isn’t a scientific hypothesis really. It’s more showing you the limits of scientific inquiry into the deep history of Earth.