Why is a raven like a writing desk?
I’m sure I have no idea, but I do know that this is the kind of question that could inspire countless novels. Our stories need to have some sort of purpose and the reason we can take an idea and write it infinitely many ways is because it must be an idea that is subjective and complex and cannot be answered or solved in one definitive way, or is an idea that gnaws at you when you should most definitely be doing something other than considering the complexities of life. Even when the point of a story is one that has been made before, it must be a point/moral that can be expressed many different ways.
To both state concisely what I’ve just said and to give you a frustratingly broad suggestion: Write about life. Write about people. Write about unanswerable questions.
If you write about these things, you will never run out of things to say and ways to say them.