"Ban a ton of widely used C++ features" creates a problem that is smaller than but still comparable to "rewrite it in rust." You also still have some features o

"Ban a ton of widely used C++ features" creates a problem that is smaller than but still comparable to "rewrite it in rust." You also still have some features of modern defensive C++ that can still be abused and cannot be removed from the language or made safe without something resembling the Rust borrow checker. Getting these features in the C++ language itself will be absolutely impossible, both because of massive performance implications and well as nightmarishly large ABI breaks on everything. There are various efforts to do what you are describing. I think that they are often a good idea, but they absolutely will not solve the problem conclusively.