https://www.cnn.com/2023/09/05/world/ancient-human-population-collapse-scn/index.html

Not sure how accepted this is, but seems interesting. Especially the 100,000+ years we may have balanced on the edge of the precipice.

It's been claimed regularly for years that the human line went through a bottleneck when numbers dropped close to extinction, but this seems to be work that tried to establish a more accurate estimate of when it happened. It was known that our dna shows very little variation, for which a population bottleneck is the obvious conclusion. 

This date that they've given of about 900,000 years ago, puts in in the era of homo erectus, leading on to homo ergaster. 

It could be that the population dropped to a tiny number, or it could alternatively be that an isolated population of a few thousand grew and grew, displacing or wiping out the other humans who existed at the time, rather than interbreeding with them. That would give the same signal in the dna. 

That's possible, but less likely, I would have thought, given that modern humans interbred with Neanderthals when they came in contact with them, as proven by the 3% odd Neanderthal genes that modern humans have, except for people from sub-Saharan Africa.