Just buying the raw materials to produce at that scale would be multiple billions in working capital, the CapEx would also be enormous.
They don't need to buy all the materials up front. Nor do they need a bunch of cash. Just like with the 3, they can sell the completed goods before they have to pay for the ingredients. Further, for large scale installations (or even PW installs), they can get deposits up front.
CapEx may not be so bad with the internally designed and sourced equipment.