A more specific version of this could be “Write the movie you’d pay money to go and see”, or “make an album that you’d spend money to own”.
Sometimes we calculate too much. We wonder what is popular right now, what are the trends in our industry? Who are the buyers and what are they looking for?
What’s the thing that you want to make that doesn’t exist yet? What is it that you are uniquely qualified to create? Make that.