You have just asked why we can't "just move manufacturing out of China:"
There are no individual chemical plants, there are huge chemical complexes owned by many companies with own well guarded know hows. There may be 2-4 suppliers in a row producing some intermediary product used in making of only 1 output.
Just to make the semiconductor grade hyperpure propanol you need ultrapure catalysts, ultrapure sulphuric acid, ultrapure water, and ultrapure input hydrocarbon stock. Ah, forgot, you also needs an ultrapure tare manufacturer, because bottles you ship ultrapure materials are single use.
You need decades just to replicate this. Now you need to move 100+ of such material chains.
> If it's just for historical and/or economical reason
Simple answer, yes! Taiwan has quietly swallowed near an entirety of the wider precision manufacturing industry.
It been consistently swallowing very capital intensive industries producing exportable niche products one after another simply because nobody else been taking such hard, and risky ventures. Yes, their profitability is not high, but their "moat" is gigantic.
Taiwan been an industrial titan for 20+ years, and the US only finds out about it now.