It's not really a thing in the global north, but in many places in the global south you'll find street vendors selling soup and other whole ass meals.
First reason that comes to mind I think is how many (official or ersatz) public spaces to sit down and eat (you can't really eat soup on the go) exist, and also how soup-centered the local food ways are.
I'll go to my university's library to see if they have anything on the anthropology of street food, and report back.
Indoor climbing guys are much more PMC coded than outdoor climbing, who lean more toward the dirt bag spectrum.