China executed people for this years ago and I think public trust in the product has yet to recover
My impression is that they trust anything that is not from mainland China will be better than what they can get domestically.
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.