The rumors were that the Gen 1 7nm process had terrible yields and that bitmain only had enough good chips to build a few thousand S15's, and due to the low yields they had to sell the machines below cost. It might be true. That would certainly explain the purchase restrictions on the first few batches, and short period of time they were available for shipment. I would imagine that the yields on the gen 2 chips will be at least as bad. For all the Gen 1 7nm they shipped, the network hashrate is still below were it was mid-Nov, and has probably been supported in large part by keeping older gear running via all the dyscalculia suffers that bought up those BitDeer contracts. But we shall see. If the price makes sense, and the specs pan out in the real, I'll be picking up a few S17's for the farm. If. When. Maybe.