I’m not saying a GC guarantees all safety, I am saying you can find a GC language that gives all the safety (and technically more) of rust.
My quote of “future unsafety” is that even if your code currently uses only safe rust, their will always be the chance someone adds unsafe rust, increasing the safety issues.
It just seems you can find a GC alternative that will never run into the issues rust can cause, and it will be faster to develope/change (because no borrow checker), and there is no downside.