I like how evolution almost seems prepared to dispense with an organ if it demands too much energy. We don't need to be technologically advanced and emotionally developed creatures in order to propagate our genes. We just need to be able to live and spread our seed. Strong muscles, high agility, and quick reflexes require less energy than a complex brain, whilst still contributing significantly to the ability of a species to survive. Hence, unless conditions are absolutely ideal, there's little incentive for animals to develop the kind of intelligence that we've developed. I'm not suggesting that humans perhaps aren't meant to be here. But I just think it's fascinating that we're so inconsistent with the rest of nature. We might suppose ourselves the pride and joy of natural selection, but really that's only true insofar as we are capable of surviving longer than other species. Our bodies are so hopelessly adapted to hardship, that once our technological advantage is taken away from us, our prospects become suddenly very bleak. And maybe, if circumstances become extremely difficult to endure, we might just end up losing our big brains, and end up developing big bodies instead.
Strong muscles require food, high agility is expensive, and while quick reflexes are great, what's the point if you can't coordinate them? Humans most significant advantage is our ability to cooperate in an extensive manner, well beyond anything other animals do. Each human exists as a dual being; an individual and a team member, a node and a server. This is an underestimated advantage when most people think about it. Say we are back before civilization. We are hunting Gazelle. I ask you to run ahead; you do so, we've had this hunt before, you usually run ahead. I take off after the Gazelle, ready to push it in to your trap. While you're waiting, you notice a lioness in the grass. You can choose to do a few things here, but the fact that you can make an individual decision, such as to kill that lion, while simultaneously operating within the parameters I set for you is fantastically useful in harsh environments. Large brains let you plan, react, and fight better, and most importantly you learn from mistakes beyond simple responses. If you fight a lion and survive, you will know what not to do in a situation, and can then tell others what not to do. The best advice is not to hit the sharp parts. Humans are also rather naturally talented warriors. Fight something anywhere and the first thing you'll do is pick up a rock. Its instinctive, and we know, without really thinking, how to hold that rock, how to hit best with it, and how to throw it. That's not a technological advantage, its a dude with a rock, and I'd bet on a hunting group of humans with rocks and branches against any other animal walking the planet. Last thing before I sleep, you realize humans are probably the best adapted to harsh climates,right? Sure, if you take away our complicated technologies a good portion of people will die, but that'll happen with any environmental change. Humans have occupied the world in every corner that we could reach. Mountains, tundras, deserts, islands, forests, tropics, swamps, volcanic areas, you know it. I can't think of a species as universal, because unlike say, dogs, or livestock, all of the humans in the different areas are basically the same. Skin color changes, facial structures change, but there's no longer hair, no tail, no super elongated canines, nothing. its a bunch of humans. And we did all of that without a motor to drive us. Hell, most of the human race got to where it was by walking. Sure if you have a lion bite us we get messed up, but put the lion in Siberia and it dies. Humans just make it a coat.
I don't object to your observations. I just think it's important to illustrate that a human brain isn't the pinnacle of evolution, and that the developments of our brain can still be exchanged for other qualities under certain selective pressures. It's true, that having a large brain and a sophisticated intelligence are an immense advantage, and make us exceptionally adaptable. But bacteria are adaptable also, and this isn't contained within their individual intelligence, but within their ability to rapidly proliferate and evolve. Human beings are admirable, but developing advanced intelligence wasn't the inevitable course of a species seeking survival, and I wanted to point that out.