Chinese dark factories aren’t harvesting bruisable fruits and veggies. Dark factories are specifically selected for tasks that are easily automated with extremely high precision. Most of agriculture isn’t.
In some places Chinese labor is at price parity. However the reasons why China has dark factories is government investment and an abundance of mechatronics engineers.
People build factories in China because all the other factories are in China just down the road.
None of this contradicts my previous comment though. We don't invest in automation because we have cheap labor. China is an aging society with a shrinking workforce. Here we have cheap labor and offload the cost to the taxpayer. Illegal immigration is just another part of corporate welfare which is why socialists like Bernie sanders used to be against it.
Your counter argument clearly cuts against your initial argument. Low wages isn’t preventing automation. It’s lack of an ecosystem of similar suppliers, lack of highly trained talent and lack of government and market investment.
Liberals aren’t against immigration because it is corporate welfare but because of the strain it places on the social safety net and effects on jobs but both of those could be overcome with a rational policy on special economic zones.
Please show your homework because the underlying logic seems exactly opposite of the facts.