Are we talking in circles here? My original point was that memory safety should be ensured by the OS/hardware. That way no matter how badly my program misbehaves, it will not be able to access memory outside of the sandbox. In other words, the CPU should not be able to address memory which has not been allocated to the current process. A buffer overflow should be a panic.

Even with a safe language, there's vulnerabilities like supply chain attacks which allow malicious code to use an escape hatch to access memory outside of the process. I.e. I could be programming in Rust, but one of the crates I depend on could silently add an unsafe block which does nefarious things. OS/hardware level sandboxing could prevent many such classes of exploits.