I've read elsewhere in expat forums that PRC citizen parents with infants visiting the US will load up big parts of their luggage allowance on the return trip with formula. Costco is their favorite store to use. They similarly trust the US-branded formula sold from Costco in the PRC. The general supply chain QA and integrity US citizens take for granted domestically cannot be overstated as an important differentiator until you've traveled extensively around the world. US and EU supply chain integrity problems are nothing compared to many parts of the world.
This isn't just in the US. In Australia there are have been limits on how much baby formula you can buy per day for years because Chinese parents do not trust domestic powdered milk and so there's an underground market for shipping baby formula from other countries to China at extortionate prices.
My impression is that they trust anything that is not from mainland China will be better than what they can get domestically.
> ...so there's an underground market for shipping baby formula from other countries to China at extortionate prices.
I have long suspected years ago that in the US mysterious, sporadic local news reports of a Wal-Mart, CVS, Target, or similar store getting wiped out of all baby formula or all of a certain brand/SKU were simply rings of people scooping it up for this arbitrage over eBay, similar resale/auction sites or even WeChat. It doesn't seem systematic, and was very arbitrary which towns/cities they hit and when, but I've always wondered what the real story was.
And since real reform would likely require regime change, activists outraged over the latest problem (train derailment, buildings not meeting earthquake code due to fraud, etc) go to jail for disrupting social harmony.