There is no natural tendency for apes to become more human like - any more than there is a natural tendency for wolves to become more dog like.
So you way as well have asked - “if dogs came from wolves, why are there still wolves?”.
Australopithocine are missing? Homo habilis is missing? Homo erectus is missing? Where did they go?
Lost in the mists of time...
They died out because they couldn't survive a changing environment?
They couldn't compete with a newer, smarter Hominid, and died off?
They died because of the spontaneous generation of a virulent virus?
I could keep this up all night, but in the end they died. The question remains, did they become the progenitors of the next generation of newer, smarter, stronger proto-humans or does the time line have vast gaps between these occurrences leaving each one alone with eons separating each such occurrence?
Don't misunderstand, I believe that evolution is at work and that it causes stable mutations in existing lifeforms. I have a problem rationalizing DNA/RNA arising from random amino acids. Long chain molecules, yes. Self replicating blueprints that result in self replicating complex living organisms, I remain unconvinced.
Regards,
GtG