In Stock Again.
Let me guess not profitable at $400, so it's out of stock. Soon as it's >$450, magically in stock again.
It's a miracle!

I think Ninjatech has S1 in stock
Usually Ninjatech orders directly from Bitmain though. So, if Bitmain is out of stock, then Ninjatech is too.
When I ordered from Ninja, the label said it's from Shenzen China, not Arizona where Ninjatech is based.