i would caution against taking that as gospel, afaik we don’t really know why other species died out yet, and we have very clear evidence that our species interbred a whole heck of a lot.

it’s probably a whole host of reasons that led to us surviving alone, including stuff like being able to survive on very little food, and hey maybe we to some degree simply interbred to the point that their species dissolved into ours.

imagine being a buff neanderthal and encountering these strange lithe people with less hair and suddenly that pretty girl in another neanderthal tribe you had your eyes on is completely forgotten.