Who ever said there was only 1 exodus/migration out of Africa?
That's the British model, a master-race vision called Replacement.
We know for a fact the entire human race nearly died out, at one point pinching to maybe more more than 10,000 individuals.
We don't know anything of the kind. There used to be a claim around that there was an eruption (Toba) that squeezed the human population down to 70,000 or so, so that may be what you were thinking about -- but it's been debunked.
The out of Africa theory only proves that all currently living humans are descendants of a common ancestry that exited Africa at a particular time... it doesn’t say Humans never left Africa prior, only that if they did, none of those lineages survived to current day.
A theory doesn't prove anything. Common ancestry is suggested by the fact that we're all very much alike at the genetic level, and even before anyone knew about such things, total strangers meeting for the first time seem to have had no problem gettin' down to it and making babies, so, common ancestry.
Sorry but there is evidence of previous migrations, but they don’t seem to have failed... all survivors appear to be from a single
Migration, but there is not evidence it was the first migration out of Africa
"We don't know anything of the kind. There used to be a claim around that there was an eruption (Toba) that squeezed the human population down to 70,000 or so, so that may be what you were thinking about -- but it's been debunked."
Yes...it's been debunked. I pushed this theory for years. No more.
Late Pleostocene Human Population Bottlenecks. . . (Toba)
"The last glacial period was preceded by 1000 years of the coldest temperatures of the Late Pleistocene, apparently caused by the eruption of the Mount Toba volcano. The six year long volcanic winter and 1000-year-long instant Ice Age that followed Mount Toba's eruption may have decimated Modern Man's entire population. Genetic evidence suggests that Human population size fell to about 10,000 adults between 50 and 100 thousand years ago. The survivors from this global catastrophy would have found refuge in isolated tropical pockets, mainly in Equatorial Africa. Populations living in Europe and northern China would have been completely eliminated by the reduction of the summer temperatures by as much as 12 degrees centigrade. "