Now, perhaps it is also true that Mexico is losing industrial jobs to Mexico but still seeing economic development. This is where I wonder if they are missing the forest for the trees:
Those traditional Mexican enterprises are getting a boost from the maquiladora down the street.
It could very well be that Mexican workers aren't seeing huge gains in productivity the way American workers are. American manufacturing jobs are being lost to automation as much as to outsourcing, but that allows America to still manufacture a ton of stuff. We just don't employ nearly enough people to make all that stuff.
Mexico tends to absorb jobs where there is no technological productivity growth. If that job COULD be done better by a machine, it likely stayed in the US.
This feels like economics at its worst: digging into data to find something odd and counter-intuitive for the sake of finding something odd and counter-intuitive.