That's because growing healthy food is expensive in the US. Manufacturers chase profit by cutting corners wherever possible. They are fully aware of all the toxic shit they use in the soil, etc but sweet profits are better than healthy consumers. 
Half the crap used in the US food industry is banned in Europe, and for a good reason. 

I'm all for healthy organic food (which does not exist in the US anymore by the way; buy the list expensive produce in Whole Foods and compare to regular European produce and you'll be shocked), but general population would simply not be able to afford food that is grown in accordance with the best practices. 
There is a reason why the wealthiest FLY food from the growers in Europe to consume on the American soil. 

 We are so much poorer than we realize 

 This is definitely a controversial but somewhat fair opinion. In reality, consumer only cares about the quantity, not the quality.