Things survive for no good reason. It is very common in evolution.

For example, our eyes are wired the wrong way, that is, the optic nerve goes in front of the retina, causing a blind spot and other issues. From a design perspective, it is really stupid and there is no "good" reason why we are like this, it would be like making a monitor with the connectors in front of the display. Octopus eyes are wired the correct way and it works better.

Eyes have evolved like this out of random chance, as an imperfect but functional solution, and we are too advanced for evolution mechanisms to fix the problem now.

Not knowing an underlying reason isn't the same as denying that reason's existence