The factors that influence moving production to different places around the world are many and diverse. It wouldn't surprise me to find that politics, tax breaks, generating consumer goodwill and a host of other factors were involved in Stanley / DeWalt's decision.
Individually, we might want to keep everything in the USA, but if we were making the managerial decisions, we might make the same type of choices that virtually every USA company has made regarding overseas and domestic production. Depending on where you sit in a company, things look different. Doesn't make all the choices right or good, but capitalism and profitability isn't about fairness.
That said, many DeWalt tools have been assembled in Mexico in recent years but with their newest 12v & 20v tools they've been coming from China. In my view, Mexico is better than China but worse than domestic. I'm glad to hear of the small shift back to USA assembly.
It would be very difficult to economically compete if they didn't source components from around the world because, while things CAN be made in the USA, so many consumer grade items are just not economical to produce here.
The one component that comes to mind that's required for power tools is small electrical motors. I'd be amazed too learn if any large scale production of such fractional horspower motors is still done in the USA.
I wish them luck because if our countrymen don't have jobs, how the heck are they going to be able to buy anything from anywhere?