You have to figure in the US they are dealing with HUGE regulations, OSHA, matching payroll taxes, workers comp according to payroll employee benefits, I am thinking about $100.00 cost per phone STILL worth every penny!!
$100/phone would be the very upper end.
Add in the benefit of American tax payers paying for our infrastructure, military, and space program instead of Chinese tax payers paying for their infrastructure, military, and space program while we borrow money to pay for their goods.