As far as we can tell Neanderthal populations were very small and fragile (very low genetic diversity) to begin with. So it’s not unlikely that modern human jus

As far as we can tell Neanderthal populations were very small and fragile (very low genetic diversity) to begin with. So it’s not unlikely that modern human just absorbed them. A bit like the hunter gatherers who pretty much disappeared in much of Europe during the Neolithic