The problem with Layering in Winter Cycling is that it just doesn't work very well. This is easy for a hiker, or cross country skier, they can usually just add or subtract the outer layer, but a cyclist moving at 15 to 20mph can't spare the wind shell. Then there is the problem of storing the removed layer. Unless you have a backpack or panniers this is a hassle. Of course, we aren't even mentioning the problems involved in undressing and redressing in public or in a howling wind.
Cyclists generate a lot of sweat.
By the time you realize you are too hot, you are already wet. If you don't remove the wet garment, you will chill yourself more than you think as upper layers are removed. Cyclists can regulate temperature by level of effort. Winter commuters learn to dress for the temperature. They will start out slightly underdressed , and therefore feeling a little cold.