The meat cap on spare ribs is called Fresh side and is where the majority of bacon comes from. This cap is typically around 1 1/2 to 2” thick. Sometimes they get hogs with less than 1 1/2 thick cap on the ribs, it’s to thin to make bacon. So my guess is they trim some of the fat off for sausage and leave the extra meat on the bones to sell. My guess is they make more money selling on the rib vs cutting off for sausage because on the rib you are paying for bone weight, where sausage it’s just meat and fat.I guess it depends upon whether the pig had a lot of meat on his bones. And then the packager is probably gonna sort out the thicker racks from the skinny ones.
I like how Sams cuts that breast bone off, I don't have to pay for it.