The same primary factor that drives this entire scheme, and the entire export of US jobs and industries: cheap labor, cheaper port labor, cheaper port operations in general, and cheaper truck drivers to move the goods away from the ports to points all over the US (with Mexican drivers all the way).
Most folks have about had enough and the machine knows that.
They have been getting ready for some time now. As a matter of fact they created homeland security for that reason.
Imagine that, some 230 years ago we gave them a handful of basic jobs and they are just now getting around to one of them.
I expect “them” to get us in world war three anyday now.
That would probaly solve the civil inseruction problem for a few years.