> We can gradually refactor it

Is quite a hell of a statement, when memory management issues are highly nonlocal and need some careful design upfront in order for you to nail it.

Unsafe isn't something that you can gradually clean up. Even one single flawed usage of unsafe (an ill-assumed invariant) can poison the whole program in scary ways, and might require a total refactor of your codebase to fix it.

You're not helping your case.

So if I use Zig, I need to do all of that perfectly from day one and I don't get any help from static analysis to do it. Or else I've poisoned my whole program in scary ways and will require a total refactor where I still won't have any help and once again can't make a single mistake.

You realize that what you're describing is inherent complexity in memory management? This is not something that you can dodge by using Zig, it's just part of the domain.

The difference is that in Rust you get strong guarantees for everything that is not inside of unsafe and clearly demarcated areas where things might go wrong. Even if you never eliminate a single unsafe block, the clear demarcation is valuable as an artifact in its own right.