Even with labels, most people would not read them.
We dont' eat pork. I grew up being taught to read labels ALWAYS, to make sure that there was no pork in it - no pork in sausage or snuck into beans, no lard in baked goods or crackers, always ask people if there is pork in something if there is a potluck at work, etc.
But most people don't read food labels. They don't want to read food labels. In twenty years of nursing, doing diabetic and cardiac diet teaching and trying to get patients to read food labels, I can tell you that most people do NOT want to read food labels. If people read food labels, then they would have to be accountable for their food choices. They would see that there are sugars in their food, starches in their food, preservatives in their food, and the worst one of all - they would have to see that there are CALORIES in the food they eat and that the serving size is less than what they usually eat of a packaged product.
It doesn't matter what it is that is in the food, they don't want to know because if they don't know, they can blame it all on the manufacturers or the government or whoever - because they don't want to be held accountable for what passes their lips.
They want it cheap, they want it tasty (and to many people, veggies are not tasty unless cooked to death and drowning in butter etc), and they want it fast. And as long as they don't know what is in their food, that is ok with them as long as they can buy what they like, when they like, and have it "their way".
Yes, there are more people today that want to eat healthier and they read food labels. But by and large, the general public isn't interested in being that accountable for their decisions and reading food labels.