All good comments, but still, if the mechanization was replacing as many workers as some here think, it would soon become more feasible to move some of this highly mechanized work to the areas where most of it would be sold.
That’s what happened with automobile parts. There are a number of other industries where it has been commonsense to relocate the greater part of the operation to the point of sale ~ abroad!
They expected a vast number of sales throughout South America.
Subsequently the international shipping container with it's intermodal capabilities (truck/rail/sea) has pretty much wiped out that advantage but more recent threats to make casting more expensive has the same engine manufacturing interests looking at EXPANDING operations in South America in the exact same places.
BTW, truck engines are are not exactly designed and built by an interlocking zaibatsu, but they are !!!!! The subcontracting in that line of business is truly incredible.
You forgot the main problem. If it were Just about hourly wage costs Then yes your assumption would be close to truth BUT leaving out that one huge factor invalidates the premise of which you speak.
That one thing you left out is the unfunded mandates that US Businesses have to endure from the Federal, State and Local governments. Not to mention the kickbacks and political back dealing they must engage in just to open a business.