> C++ has a standard library and smart pointers that eliminate a lot of errors with dangling pointers, and if people use those exclusively

You can't use smart pointers exclusively, because there is no "smart observational pointer", and there cannot be one, because that would be a reference type checked by a borrow checker, which is exactly what rust uses.

You can emulate it with shared pointers, but then you're left with basically a reference counted language. Why not using swift at this point? Also this creates a semantic impedance mismatch that tends to manifest with cycles.

Source: walked a codebase that would (ab)use shared pointers