I get your point. Sure, it doesn't apply everywhere, but it applies in 70% of the world. it hasn't snowed here since '92, but we do have chilly winters, it's -2C right now, and I just drove 12.5km to get home, through heavy crosswinds and zero visibility. I just fucking love riding on two wheels, cold or not. It's enjoyable, it relaxes me. I leave the problems at work on the road and get home happy as a clam.
Regarding groceries/passengers, etc., well, as I said, I leave 12.5km away from the city, and the stores around are closed by the time I get home, so I usually do my shopping on the city. Yesterday I brought ~5kg of meat and ~2kg of vegetables using just the storage below the seat and a small backpack. I do have additional storage (saddlebags and a top-box) that I can just attach to my ride if needed. And I'm used to riding with one on the back, not a problem. I've taken two people too many times.