"Why in the world would they? Your question shines a brutally bright spotlight on your ignorance."
Nice try, but YOU are supposedly the 'evolution' expert, so YOU need to answer why the apes which live today somehow managed to escape the evolutionary process which gradually turned their ancestors into humans. How did they manage to cheat nature and escape their evolutionary fate?
Why are there no written historical documents recorded by humans detailing their (allegedly) intelligent, but sub-human beings that contested them for land, food, etc?..."
"Huh? Your question shines an even more brutally bright spotlight on your ignorance."
I don't expect a Darwinist to be able to think deeply enough to conceptualize this rather basic dictum, but if over millions of years there were a gradual change where apes were transforming into humans, there would be long periods where the evolutionary process remained static, and your part-monkey-part-human ancestors would have thrived and left endless amounts of fossils from their bodies, skulls, shelters, weapons, tools, etc. But we have no such thing, all we have are ape fossils and very primitive human remnants. There is still NO MISSING LINK. "Piltdown Man" is still the closest thing you've got to the proverbial missing link.
But to take your little Darwinist mind even deeper into my thought, the various climate and environmental differences on the earth would have certainly affected the 'evolutionary' process of these apes, allowing for some of them to remain ape-like for a longer period of time than the others, others to evolve closer to human beings, and still others to have already fully evolved. If this did not happen, then you don't have evolution you have UNIVERSAL INSTANT CHANGE, which contradicts everything Darwin theorized.
Now, if you have fairly intelligent apes, other even more developed apes, apes that are now almost human, and recently evolved but fully human people, then, (unless they were all prototypes of modern day peace protesters), you'd have inevitable clashes between the species. There would assuredly have been battles over territory, food, prey, water, shelter; and even clashes for fear of each other.
Fully developed humans are extremely intelligent beings. They build marvelous structures, they make fascinating weapons and tools, they leave wonderful art everywhere they exist, and they develop language. (In fact an effective language would have developed even before they became fully human). With this language, humans speak, write and record things. They make carvings, drawings, paintings and leave writings. In short, they leave some history of themselves; they are humans, after all. Why didn't these humans leave any record whatsoever of there being another form of being which was close to them but more primitive, more ape-like? Where are the remnants of the inevitable tribal battles between these closely related species, replete with bones from both humans and semi-humans? Where is the decisive evidence of evolution aside from in the minds of Darwinites?
For you Darwin worshippers, the many holes, missing links and endless unknowns of 'evolution' are conveniently filled in with astounding conjecture, and you trust in this conjecture and theory with a blind faith that is baffling because it trusts in no intelligent Cause of life, no reason for anything. And yet we are REASONABLE beings. But this kind of blind faith is not really faith at all, it's the perfect example of human pride.