Interesting. I haven't pre-ordered an iPhone since the iPhone 5, and that particular phone I pre-ordered through Verizon (back when contracts existed!). That said, I don't know what's normal and what's not. I just assumed that you could get iPhones unlocked on day one.
If the iPhone 8 is available carrier-free, I ponder if the X will be available in the same way on preorder day? At this very moment, you are required to choose a carrier for the iPhone X (even though pre-orders aren't allowed yet).
If you read the FAQ's at the bottom of the preorder page, it appears that all iPhones come unlocked, even if purchased through a carrier; save for this clause: "Your iPhone will only be tied to your carrier if you choose carrier financing from AT&T or Sprint."
Would someone explain to me why you must choose a carrier option, then? Like what is the benefit/deal between Apple and these carriers?