Lighting is a very small fraction of our energy usage (about 5%): https://www.eia.gov/tools/faqs/faq.php?id=99&t=3

If we built our houses right, we could drastically shift energy usage requirements for heating and cooling to daylight hours (utilizing thermal mass storage like https://www.steffes.com/ets/ )

Also you can't underestimate moon light either in premodern times. Deep in the trees or an urban landscape with tall buildings all around it is less reliable, but even a half moon on a clear night without washing your vision out with bright artificial lights leaves you with a ton of light. And even when overcast you aren't completely blinded at night as long as you have a decent amount of sky above you.

I think the idea of people sleeping as soon as the sun is down and not just doing low-light activities even 3000 years ago as ridiculous despite being a pervasive idea.