No big fish needs to pre purchase them. Anything you get made in China will be stolen - i.e., the people who work in the facility WILL make extra of your product once you give them the design. So, Yifu gives this Chinese company the design, and orders 2 million... they will run off 2 million for Yifu and 1 million for themselves and not pay Yifu anything for it. That is why when you go to China you can purchase brand name clothing without the brand tag for like 60% off the msrp.
You have to expect that the hash rate will go up much more than the theoretical from the nominal chip orders alone due to this. When you get something made in China you are pretty much guaranteeing that your product design will be infringed upon and your tech stolen.
Well, that's a well-known fact about China-based manufacturing. But seriously, I refuse to believe that TSMC is into it as well. They're not a garage-based assembly line powered by biorobots who work for food, but a world-leading semiconductor company. How could they produce extra chips for themselves?
Because YiFu doesn't deal directly with TMSC, he deals with someone that deals with someone that deals with someone else. He probably pays three times what they actually cost from the fab, and someone else in the process makes sure that twice as many chips get produced, etc...
They seem to be shipped from Massachusetts and claim 2-4 day delivery. Hmmmm.....