How come there is no ape species more human like than chimps or bonobos? Why is there such a huge gap? You would expect to find living gradations of species leading up to human, right? There should be sub-humans and sub-sub-humans and sub-sub-sub humans walking around.
Please don't post ad hoc explanations with no scientific evidence to back up it up.
Saying they are not alive today because X reason without any scientific evidence to support it is not science, but a cheap cop out.