I fully expect formally verified C to become the standard for any reasonably critical software. It's astonishing how easy it is to crank out program equivalence proofs these days...

The real defensible reason is that with current tools available you can write perfectly safe (safer than Rust even) C++ code, while avoiding the horrid Rust compile times and without needing to pepper your code with unsafe all over the place. LLM's can help you formally verify your code and extensively fuzz/test it to the point where you can actually be sure (ie prove) that the code is safe, without really relying on Rusts compiler. Lastly, C++ lends itself more naturally to hardcore optimizations than Rust. But ultimately it really, _really_ comes down to a) Rust's horrid compile times and b) Rust's horrid metaprogramming support (this even kills it for LLM generated output because it wastes tokens).