I am familiar with that number but this does not address the point the top-level comment is making. The commenter claims is that there exists a class of problems where lifetime and ownership are not knowable at compile time, and makes the claim that for these problems Rust is worse than C++.

Well, I don't know what "worse" means in this context. If it means "less memory safe", that's clearly not true: RefCell and Mutex are formally memory safe, while the C++ equivalents are not. If it means "less correct" in a more vague sense, then that's essentially an argument that Rust programs have more bugs than C++ programs, which seems dubious and certainly not something I'd accept at face value.