Performance drop of 2x for memory safety critical sections vs Rust rewrite taking years/decades, not even a contest. Now, if that drop was 10x maybe, but at 2x it is no brainer to continue with C++. I'm not certain Fil-C totally works in all cases, but it is an example of how the ecosystem will evolve to solve this issue and not migrate to Rust.
What would you consider to be a non memory safety critical section? I tried to answer this and ended up in a chain of 'but wait, actually memory issues here would be similarly bad...', mainly because UB and friends tend to propagate and make local problems very non-local.
