In any way trying to be harsh, no way, just giving my point of view. I think that you mean USA instead of America, America is the continent, from Alaska to Patagonia. Cubans, Mexicans and Argentinians are Americans too.
But the reason why companies from the first world go to manufacture in the third world is just money, more money for them and less costs, also less regulations about being friendly with the environment. Basically many companies get as much as they can from staff in poor countries, generating pollution and earning more money. Just see China, India and other countries, full of rubbish, rivers contaminated, staff committing suicide because of the number of hours they work. Crazy world!.