Ask HN: How does Apple achieve both secrecy and quality for a release?

I know there are several counterexamples, but in general I'm impressed that Apple manages to keep new products/features under wraps until a major event, and then the product is in stores a couple weeks later with pretty high quality (user experience, reliability, minimal major bugs, etc.) Can anyone who has first-hand knowledge shed some light on how this is achieved with what I assume is quite limited user testing to contain leaks. Even working on products with multiple public betas and customer feedback sessions, it's hard to hit a high quality bar with a product release.