I personally think the amount of stock is far higher than people expected
There is absolutely no way for anyone here to know this. Shipping slipped almost immediately from Apple, and within an hour or two dropped to 5-6 weeks. This can be due to: A) Stock was extremely low, and demand was fairly low, allowing for those who are quick to get them fast, but stock to run out quickly anyway. B) Stock was fairly decent, and there was good demand. C) Stock was huge, but demand was astronomical.
There's simply no way for us to know where on that line of stock vs. demand this lies. They could have sold 2 million phones or 20 million phones.