That scenario doesn’t seem too likely, even if the lower figure of 70K (or as some would have it 40K) is accepted.
The problem is perhaps analogous to the search for exoplanets — when the first one was verified back in the 1990s, the technology was such that only very large bodies could be detected. Now nearly twenty years on bodies only 2 or 3 times Earth’s size can be detected.
With perishable materials, much less will survive over these huge intervals; woven material was used a very long time ago, but has only survived in the form of the imprints left on, say, clay. But the stone tools, arrowheads, etc, will be there for millions of years.
The oldest multirow (cultivated) barley sample AFAIK goes back to RC 14000 years ago, dug up in the Near East somewhere. It’s amazing that it survived, but it pushes back the verified age of agriculture. Postholes from structures rather like longhouses have been dated to 800K, and while it’s possible that a hunter-gatherer culture may have built shelters, the very nature of a moving food supply makes it unlikely that some form of agriculture was NOT being practiced there.
For much of the last 2 million years the oceans have been reduced in depth by glaciers on the highlands of the continents, and it’s perfectly likely that most of what we’d consider human prehistory left its traces on what is now the continental shelf.
Afrocentrists have this "thing" about the early Egyptians being black Africans. Personally, I think that agriculturalists from much further north came down the eastern Mediterranean coast, found the very fertile Nile valley, and displaced any Africans who might have earlier been there. Egyptian civilization followed.