When it's bright outside it's only sensible to keep artificial lights off as it saves you money and if you have decent windows the quality of light in the building will be fine.
Now why don't more people apply the same principle to heating? Most do the basics of turning the heating off when it's warm out and trying to insulate their homes, but not a whole lot of people design their homes or buildings to be entirely heated or cooled by the sun. According to the NYTimes there are only 15,000 passive solar homes in the world, a fact I find very hard to believe as ancient societies have been building south facing passive solar homes for a while.
The article is an interesting read because of what it alludes to. The article is about passive solar homes in Germany which is now at the forefront of passive solar heating technology....an interesting thing for a country that is around the 50th parallel north. Germany is also one of the worlds leading solar electric and wind powered nations, it's no wonder that the team from Technische Universitat Darmstadt won 2007's solar decathlon.
The lesson to learn from Germany is to recognize your weakness and work to fix it. As T. Boone Pickens said they realized they don't have oil so they decided not to base their economy on it. While they don't have much wind and they don't have much sun, they have more of that than oil.
Plus wind and sun is free...oil, not so much.