Yup! I didn't work this into the post, but this is in fact exactly (more or less) the goal. Chandler even explicitly says "Maybe we can eventually convert some

Yup! I didn't work this into the post, but this is in fact exactly (more or less) the goal. Chandler even explicitly says "Maybe we can eventually convert some future version of Carbon to Rust, who knows." Whether that is going to happen (or is viable) is unclear for now, but it's pretty clear that a migration of C++ to (idiomatic) Carbon will probably involve at least a few steps.