Somewhere along the theoretical highway of evolution apes took a left turn and humans veered to the right. human knowledge has expanded at an incredible rate. this is not the case with apes, even though chimpanzees cohabit with humans.The bridge between humans and apes continues to lenghten. their inability to "evolve" is one of the missing pieces of the puzzle.
Higher intelligence is not automatically an evolutionary advantage. Cockroaches are nearly mindless, but they fill their environmental niche quite nicely.
Chimps and other apes are succesful in their environmental niches. However, humanity's domination of the planet has had an impact on their population.
What "left turn" do you imagine apes took?
More accurately, the lineage which eventually became humans managed to hit upon some mutation(s) which achieved an evolutionary breakthrough in brain capacity/ability.
The bridge between humans and apes continues to lenghten.
There's no evidence that the gap in mental ability "continues to lengthen". Humans today are no more intelligent than humans of several thousand years ago. Yes, we have continued to accumulate knowledge, but don't mistake culture for biology.
their inability to "evolve" is one of the missing pieces of the puzzle.
You have yet to demonstrate that they actually have any "inability to evolve". In fact, modern apes have certainly evolved beyond their ancestor species of several million years ago.