A Surge in Winter Commuters

Nothing beats a balaclava, down parka, and winter boots, in my opinion, turning a
cold weather commute into a pleasant affair.  

Is it the fat biking explosion, better education, studded tires, or something I can't quite put my finger on that has contributed to more winter bike riders? Or is it a natural extension from an uptick in fair weather cyclists? As an avid bike commuter, it took a job change and a route that is safe, for me to ever consider riding in the dark, not to mention becoming comfortable commuting in sub freezing temperatures. I still haven't tackled snowy conditions, nor do I plan to, but there are a growing number of cyclists who refuse to let mother nature get in the way, like Freezing Saddles participants, Bri at Bike Like Crazy, and Doug at Four Season Cycling, all proving that it can be done.

What is driving the winter riding craze?