I bike to work and back every day in a USDA 7b zone (the mean average annual extreme minimum temperature is -15 to -12.2 C).

I think the range of comfortable ambient temperatures is quite a bit wider if you're willing to invest money in proper clothing (I justify it by "saving" on gas, car ownership, etc.).

At 0C with decent gloves, you're fine. At -10C, good gloves and headwear are essential, but the ride is still pretty pleasant.

IME, moisture is a bigger issue than temperature. It's the biggest cause for me not biking around town. Biking in (heavy) rain or snow requires more (and more expensive) of mental and physical prep work, and more regular maintenance, and some days I just don't want to put up with it.

On the other points, I mostly agree, although discreetly-accessible showers on both ends of the journey go a long away towards mitigating social status.