Evolution is not a process of finding a global optimum, just a local one. And traits which have no impact on the chance for a species to reproduce just get carr

Evolution is not a process of finding a global optimum, just a local one. And traits which have no impact on the chance for a species to reproduce just get carried along for the ride. An obvious example of this is the Laryngeal nerve. Fish evolved with this nerve being a simple straight line between the brain and larynx. However, in animals which evolved from fish and have necks, we see that the nerve is "trapped" under the aortic arch in the thorax. So this nerve ends up looping through your neck to reach your thorax. Giraffes have this nerve going all the way down their neck and back up again. But this inefficiency has no impact on the survival chances of a species (if your neck is severed you're dead regardless of whether you have an additional nerve running through it) so it's stuck around. So, there definitely are traits which objectively have no benefit or detriment and have just stuck around. You could argue even some late-life conditions which are detrimental also "stuck around for the ride" because people late in life don't reproduce and thus there is no evolutionary mechanism to affect such traits.