> All of such cases require unsafe blocks in Rust.

It's true that Rust makes it much harder to leak memory compared to C and even C++, especially when writing idiomatic Rust -- if nothing else, simply because Rust forces the programmer to think more deeply about memory ownership.

But it's simply not the case that leaking memory in Rust requires unsafe blocks. There's a section in the Rust book explaining this in detail[1] ("memory leaks are memory safe in Rust").

[1] https://doc.rust-lang.org/book/ch15-06-reference-cycles.html

My comment is more of an answer to this

> You're gonna be dealing with issues involving "peaky" memory usage e.g. erroneously persistent references to objects

I use Rust in a company in a team who made the C++ -> Rust switch for many system services we provide on our embedded devices. I use Rust daily. I am aware that leaking is actually safe.