1) Are you counting ramen as soup? I love ramen and eat it year round.
2) If just non-ramen soup, I'd say pretty rarely in the spring/summer, a bit more frequently in the fall, and then at least a couple times a week in the winter. We really like making soup when we can because it's not that labor intensive and can feed our family for at least a couple days, often longer. Chili is good for this too.
3) Are you counting chili?
I do think assuming people have soup daily is a bit much. I think my dad does, because he loves soup, but the average person no.