Why do we need to be? Say human intelligence evolved so that we model real world events such a mammoth hunt mentally ahead of time and use simulated outcomes to

Why do we need to be? Say human intelligence evolved so that we model real world events such a mammoth hunt mentally ahead of time and use simulated outcomes to craft weapons / preposition different hunters based on their skills. Would AI necessarily need to hunt or worry about energy intake/self preservation/producing offspring? It can be powered by direct photosynthesis (solar panels), hibernate when energy is in short supply and make backups to safeguard against future physical damage. Seems like we should think through the tasks that we need AI to help us with - climate change, medicine, space exploration, etc - and design systems for such tasks as efficiently as possible rather than trying to monkey ourselves. And sure, some day AI may develop its own purposes that are different from its origin, just like humans decided they like music. Doesn't mean that a caveman shouldn't have dedicated his attention to the next meal rather than worrying about being sophisticated.