I'm at around 2,500 factory tanks produced (estimated from my current progression on the "collect xxx amount of tanks" questline. I completed the "Produce 1,500 tanks at the factory" questline loooong ago), and I only got one five star from it.

But yea, the main conclusion of the original post leading to that discussion is that the free daily draw doesn't have a chance to get a five star. Still, it's like, 3-25 blue prints every day so it does help in that regard, at least.