I find the obsession with "natural light" funny. I am sure the light at 35,000 feet is different from what we get at sea-level after it has travelled though the atmosphere. The natural light is in fact more harmful since metal would absorbs a bit of the harmful cosmic radiation vs the plastic windows.

Most people are trying to kill 10-15 hours and the best way to do that is to get some sleep. Needing light is one thing (and that is why you have overhead or snake lights); requiring natural light is being completely selfish IMHO.