> the main difference between C++ and Rust is the cruft that C++ has accumulated over the decades,

The pace of change in C++ considerably higher. Rust has regular releases, but the changes to the language tend to make it simpler to use as they remove limitations and improve the std.

Also it is not just cruft even if you ignore all the safety that Rust provides by default. The package system and ease of compilation alone makes the jump worthwhile.