It's not the factories are in China so much as the entire system is in China. They have entire categories of engineers that barely exist in the rest of the world. They have entire industrial districts with multiple manufacturers to source parts. There's really nothing else like it on the planet. They organized to be the low cost producer. They are very, very good at integrated production. 

We'll see in a minute. We've lost a good percentage of the worlds helium production from Qatar. Helium is heavily used in Chip Manufacturing. That's gonna leave a sting. Just how integrated now ARE we? Probably more than we'd like to realize. Way more than 1929.