A big chunk of people on this site are not straight up backyard poultry keepers. I am an example of that and have capacity to do some limited integration with livestock that are grazed.Between the changing nutritional needs of chickens and there being a lot fewer large, integrated farms (Meaning various types of animals and crops raised) around, I think there are a lot fewer places the old way would “work”...especially places that have winter seasons with limited insect activity and plant growth.
Are there places it’d work? Probably. Are there more places that’d require some supplemental feed (be it chicken feed, grains, food waste, or “other”)? Probably. Is much of that within the reach of your average backyard flock owner? Probably not.