If humans evolved from apes or chimps, why are the chimps and apes still here?

This is a part of the evolution theory, which is arguable. Mainly understand that Charles Darwin proposed that as living organisms we all have one single common ancestor. Many all living organisms are more than 98% alike in DNA. This doesn't mean that humans evolved from animals such as chimps and apes. Often, I think this analogy is made due to the so called physical similarities and features of humans and chimps and apes.

Chimps and apes are still here because humans did not evolve from all apes and chimps.