The startup time is significant and VC money doesn't go into BTC mining. Furthermore, the engineers almost certainly have to live in China and have engineering

The startup time is significant and VC money doesn't go into BTC mining. Furthermore, the engineers almost certainly have to live in China and have engineering / fabrication experience there. And you can virtually guarantee your first product will be terrible and obsoleted by Bitmain nearly immediately. Manufacturing costs in the US wouldn't just be high, they would be impossible to actually get done. MOQ on something like this in American factories wouldn't be in the 100-500 range, probably not even 1,000. American factories are extremely non-agile, non-risk taking, and generally do not serve startups very well. BTC being over $10k is a very new thing, too. The insane mining profits at a 1MB blocksize + $10k+ price may not last and is a new signal. It takes a lot of time, effort, luck, and perseverance - and Jihan is a formidable enemy. Sometimes it's best to just avoid a high-risk area where many, many others failed.