Defaults matter. Owned types are the default in Rust and opt-in in Swift. As a consequence, by default it's safe to assume that any Swift code you fine in the wild isn't making use of owned types.
Yes, it supports it. But is fundamentally not based on the idea of zero-cost abstraction from where I see a lot of Rust features being derived from. So crates I pull in must obey it too - it's not optional (you do have unsafe to watch out for, but that's an easy grep).