No, because those costs are paid regardless of how many packages you receive from China. So sure, people living in the US are paying those costs "as a whole",

No, because those costs are paid regardless of how many packages you receive from China. So sure, people living in the US are paying those costs "as a whole", but you don't pay any additional cost when you order a package. It's like how driving on public roads is free, in the common sense of the word, even though of course the costs are still "paid" somehow, by somebody.