Is it possible that sleep is a vestige of the lack of consciousness that earlier life had? Like how we have tailbones and whales have leg bones and stuff. Sleep (unconsciousness) could be our natural state, but awaking up and being aware of your surroundings is more beneficial for organisms that hunt for their food. So organisms started to gain consciousness, but since their natural state is unconsciousness, they still need to sleep. Think about it like this: the first species to grow fins didn't just instantly develop a perfect fin overnight. A flap or protrusion of skin or whatever would have slowly over numerous generations start to become movable as more and more nerves and muscles grow there by chance. It wouldn't have been completely movable overnight, just like how the ability to stay conscious (awake) would have developed over numerous generations.

Though we can't get rid of sleep just like how we can't get rid of our tailbones or how whales can't get rid of their leg bones. Over time, vestigial limbs change and eventually go away, but maybe sleep has stayed because it's beneficial for organisms to sleep. There's something about the brain that makes it unable to stay awake for a long time, and that inability can be traced back to the first organisms that gained a sort of consciousness. Perhaps a few hundred million years from now animals will no longer need to sleep.

Most of life on earth is not conscious (plants, bacteria, etc...) which just proves that sleep and unconsciousness is our natural state. Even a lot of animals sleep for over 80% of the day. Consciousness is a rare thing for organisms, which is why it's possible that sleep is a vestigial habit of sorts