Labor costs are lower in much of Asia, but it's not that simple. Shipping costs, risks to IP, loss of flexibility and accessibility to the manufacturing operation all factor into the picture. There are plenty of examples of manufacturing operations returning to the US for these reasons. Germany is a higher cost labor market than the US yet you don't see much of this simplistic scenario where physical operations inevitably flee high wages.

The big issue driving away these operations on net is the regulatory nightmare of employing Americans and running a plant. You have OSHA, the EPA, and an ever growing body of employer mandates to contend with. Also, the US is now a high tax country from a business perspective.