Mostly that’s due to how much restructuring would need done to fix it. Not really because we’re wired in the optimal way.

The left recurrent laryngeal nerve loops down around your aorta and then right back up parallel to itself because as the heart moved away from the head in evolution, the nerve was pulled down with it.

Could you reroute this nerve and still function? Yep, it would even reduce latency and just the amount of nerve tissue needed.

So why doesn’t evolution do this? Because it can’t…probably…

In order to reroute this nerve, you’d likely have to change how your nerves and heart develop in the first place. That would take significant changes to the genome and said changes would have cascading effects on the development of other systems. You’d need to deal with those effects to keep the rest of the organism organized like it was. (Just realized is kind of reminiscent of the transfer learning problem in machine learning, huh)

Point is, your body is wired the way it is because the “tech debt” that lead to bad routing is too much for evolution to fix easily. Much easier to just deal with it duct-tape style than refactor the whole body.

There are probably many more things like this, like our retinas being “reversed” where it likely would be better the other way, but evolution can’t fix such a primary structure so easily (our retinas develop from our brains), so instead it tries its best to make do, and we get specialized glial cells to be as transparent as possible and a neocortex capable of pattern filling in blind spots.