The Future Is The Past And Vice Versa

If there was truly a god,
Would he abandon the first versions of ourselves?

Item #: SCP-XXXX

Object Class: Safe

Special Containment Procedures: SCP-XXXX is, in technical terms, it's own containment cell.

Description: SCP-XXXX itself is the (now proven) theory that there was a civilisation of humans before us, with the same structures and the same companies. The products and businesses, etc we have at this very moment- existed long before they were created in this time period.
Rather easy to understand, until you realise that an SCP Foundation exactly like this one, with the same documents, same sites and same design existed centuries before the first land animals crawled out of the oceans. The skeletons of certain SCPs have been found in certain excavation sites set up by the foundation, (SCP-096 somehow deceased, SCP-682 still showing life signs but immobile and weak- stripped down to it's skeleton basically dead¹ , A black and brown goop later identified as SCP-106 ) Those were some of many SCPs found in the excavation sites, however not all have been discovered.
The evidence found in the excavation sites were sent to be evaluated and, the onsite scientists in Site-19 estimated their age to be inbetween 4.2 billion and 4 billion years old, which would mean they existed 2 - 4 billion years before the first life form we have recorded (a form of micro-organism) ever existed.
Advanced technology has been discovered, we have reconstructed them in the model of what we think they looked like, we have managed to replicate some of the technology. They have been used in certain containment cells (corrosion proof metal, hover technology able to support up to 200lbs of weight and a more advanced model of a fighter jet). However we have had to be cautious whilst digging, as we have come across one physical memetic hazard²
Skeletons resembling ordinary human skeletons were found along with all of the above, the only difference was that they had 28 ribs instead of 24, and webbed feet.

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If we're not the original humans, and we weren't aware of this- the possibilities are endless. We could be robots, this would explain why we have recreated the companies, etc. Maybe we're just in a simulation? We could be aliens that have taken over the planet, and we have eventually forgotten doing it. Maybe we come from mars?
Ignoring all of the above, how were they wiped out? Nuclear explosion? Greenhouse scenario? Endless possibilities.

Footnotes

1. The SCP-682 duplicate has been destroyed, meaning through the ages it has grown extremely weak and fragile compared to the live SCP-682. This suggests perhaps the SCPs before our SCPs were weaker (perhaps our SCPs evolved from their's?).

2. One researcher was killed whilst dusting the dirt off of the memetic hazard.