I'm not convinced, because you're conflating too many things here. Ownership and borrow checking are always compile time concepts. There is no language runtime

I'm not convinced, because you're conflating too many things here. Ownership and borrow checking are always compile time concepts. There is no language runtime involved. If you think of C as a magic language then start today and get that idea out of your head. If locking and unlocking semantics are a good fit for whatever you are doing, then you can just do a lock implementation setting whatever memory mapped registers you need. There is no constraint here whatsoever. Nobody is advocating for separate atomics in every little object in Rust. That's a Java idea that failed miserably long before Rust was even around.