Rust Blogの2018-11-29の記事「A new look for rust-lang.org」に次の記載がある:

We have also revised the slogan. Historically, it has been:

Rust is a systems programming language that runs blazingly fast, prevents segfaults, and guarantees thread safety.

Like the bullet list of features, this doesn't convey what you can do with Rust. So we've updated the slogan:

Rust: The programming language that empowers everyone to become a systems programmer.

ここで「システムプログラミング言語」としてのRustから、現在の「効率的で信頼できるソフトウェアを誰もがつくれる言語（A language empowering everyone to build reliable and efficient software.）」としてのRustに変わったらしい。