For the most part, lifetime is inferred from scope, so there isn't anything special to figure out; objects live exactly for as long as you can see and use them. This also includes such things as lock handles, or references to refcounted objects.

Only in the most trivial cases. Tons of real Rust uses copying or RC/ARC or even unsafe to avoid dealing with complex lifetimes because it's... complex.

Copying, refcounting and locking work within the exact same semantics. They're among the most typical tools that are used to transmit or share data, so I'm not sure why it should be strange to see them used in most real programs?