Labor cost is a part of course.... But the bigger thing is that the entire manufacturing process from near-raw materials, through individual component manufacturing, and final product assembly are all located within just a few miles of each other. Things aren't being shipped across the country multiple times through the process. When manufacturing transportation cost is essentially zero, there is a lot of inherent cost and time savings.

They manufacture so much because it’s cheap to manufacture there and that comes at some costs like putting very little value on people and their labor.

Then we should have prioritized worker treatment in our trade deals. We naturally didn't because we not only place no value on workers or their labor, but were also willing to forfeit the race to the bottom.