Demand increases due to population growth. Population goes down, growth goes down (broadly speaking, some caveats and nuance as always depending on some goods or services).
Or demand increases due to some major new factor (which has happened a few times in recent history) that basically enables new energy extraction, or new resource extraction.
But over very long periods of time, it does seem to mostly be connected to population.
Edit: https://journals.sagepub.com/doi/full/10.1177/21582440177360...