The minute they opened up the borders to goods with minimal tarrifs, the labour will go to the cheapest marketplace. Now they can use slave labour in China and have full access to American markets.
Of course, if you undid all that, yes labour would come back here but your $300 iPhone with telco subsidy would now cost $800. All the cheap stuff you buy weekly (that comes from China) would cost 2-3 times its current cost. Question is if you were doing the minimum wage manufacturing job, would you be any farther ahead?
You incorrectly assume that the price of a product will necessarily be linked to the cost of labour. As it is, the labour costs of most electronics are dirt cheap. Iphones cost so much money because Apple knows people will pay that much for it. It's not about the cost of the product but the profits of the company.