It's a goal of Rust to be simple--one look at the RFC repo is enough to see how important that is in the language design--but there are other goals too. In part

It's a goal of Rust to be simple--one look at the RFC repo is enough to see how important that is in the language design--but there are other goals too. In particular, nobody has successfully proposed any alternative to memory safety without GC that doesn't involve lifetimes and borrowing (and reference counting is just a form of GC).