I will agree that very few, if any, people will bike to work in the snow.
Biking in the rain or in hot weather is not that big of a deal. I cycle to work all year long, the only days I won't ride are if there is snow, or there has been a very heavy frost and the risk of black ice is high.
The rain is just water and between my rain jacket and good lights on my bike, a quick shower at work cleans me up completely.
Cycling may not be the answer for everybody, but most people decide they are not going to make cycling work for them before they even get on a bike and try.