4 Sci-Fi Villains Who Could Actually Happen (And 4 That Totally Couldn't)
...And 4 That Totally Aren't
4. Dr. Zaius/The Apes - Planet Of The Apes
The problem with having a planet run by "highly evolved apes", is that you're really just talking about humans.
Yes yes, humans didn't actually evolve from apes, but from a common ancestor that we share with apes. However, sticking a bunch of orangutans in clothes and giving them human technology is essentially misunderstanding how evolution works.
Evolution is more about filling niches than climbing some kind of ladder. Becoming human-like is not the end goal of evolution, and thinking that modern apes would eventually "end up" there given the chance is backwards.
Orangutans and gorillas are actually extremely well-adapted and highly evolved to suit their environment and, in the event of a nuclear holocaust that wipes out humanity, they'd probably remain reasonably unchanged, provided their environment remained the same. Humans evolved by total chance in response to some very specific conditions, the chances against it happening twice in a virtually identical way are astronomical.
The other issue is the timescale involved. POTA is set a couple of millennia into the future. That certainly sounds like a long time until you remember that, two millennia ago, we were basically identical to to how we are today.