You don't see it because it's rare, but it's possible and just not cultural thing anymore in "rich" countries. It's even seen as sign of poverty to do that, it's a shame, that's the main reason, along with security because of the prevalence of cars and the danger they represent

I use my bike almost daily since decades, cold and dark is not an issue (you never really feel cold on a bike as long as you're active/pedaling), rain and wind a bit more, I can carry 20kg of stuff on my bike, bags on my back and front and crate on the handlebar