Swift doesn't have the borrow checker, which means that in order to ensure safety the expressiveness is really limited unless you use RC. That's why essentially all Swift code uses RC, and Rust code rarely does.

There's a big difference between technically having manual memory management and having it actually widely used and practical.

Yes, RC is the primary way to safely manage lifetimes of reference types in Swift. You can drop down to unsafe constructs to avoid RC overhead, and I sometimes do that in hot loops.

Using unsafe to improve performance is not unfamiliar in Rust either, though Rust gives you better tools for building safe abstractions around it.

Shared ownership is routine in UI programming - think event handlers, etc. These are the apps most commonly written in Swift. Does Rust avoid needing shared ownership for these types of apps? If so, how?