I disagree. C++ often removes language features, standard library features (std::random_shuffle), etc. Also object files compiled with different standard versions often are ABI incompatible with each other, which means you can't just pick new C++ for new code, but its rather all or nothing.

You can argue that when it removes features it provides a replacement (sometimes), but that does not change the fact that if you have any reasonably large project (>1 million LOC), every standard upgrade will break your app.

One of the main reasons we write all new code in Rust and are migrating the C++ code base step by step to Rust is because Rust offers infinitely better backward compatiblity guarantees than C++.

Rust never ever breaks your code, and you can opt-in to newer Rust editions for new code only, and these are ABI compatible with Rust code written using older editions.