I also sincerely doubt that Rust code bases will look the same in ten years. It supports functional and OO paradigms and it's attracting very different classes of programmers. Recently someone wrote a post about difficulties with some OO concepts in Rust, and a top reply said that they never encountered such issues because they program in a functional way.
Go is an exception here, but as soon as they extend the language in a significant way (e.g. templates) differences will start to appear.
C++ doesn't have an idiomatic style because it's used in very different ways by different people. It's impossible to have a fixed style and address the mass market.