Perhaps the more appropriate advice is : Use the right tool for the job.
Use C++ for writing a high performance library or a database engine.
Use Go or Java for writing a server.
Use C for writing a kernel module.
Use shell scripts for automation.
Use python for trying out ML ideas or heavier duty scripts.
Use Rust for ... I'm not quite sure what it's the right tool for yet. I suspect it's trying to become the right tool for all of the above and not succeeding much in practice.
Database engine, no way. Look at the internals of modern ones. Very very intricate pointer based data structures that you'll pull your hair out replicating with Rust.
Again, it's not like it's impossible. You can certainly accomplish it by treating it like a puzzle but using the right tool will have better results.
But when you look at the disaster that was c++ for cloudflare, and the switch to rust.
This is precisely the argument given against rust for video games: too much typing induced by memory safe, which is too restrictive.
Is there any use if your c code works, the advantage of rust over wasm is the easy-to-use packages (which is a pain in c++), and the ease with which you can make a wasm project with wasm-pack that generates the wasm, js and ts interface.
There really are a lot of libraries that support wasm, it's even a problematic point raised in the article on bevy, with wasm support (so webgl) limiting the api.
A C++ replacement must have really strong and seamless C++ interop to be considered by anyone currently using C++. You can't have a C++ replacement by ignoring existing C++ users and libraries, no matter how good the the language is.
Swift from Apple and Carbon from Google are stronger contenders at this point.
No language from Apple / Google / Microsoft / whatever can ever be a serious replacement for C++. When the development of the language is dominated by a single entity, the risk that the interests of that entity override those of other users is simply too high.
Vendor-specific languages are fine, if you are developing something for that vendor's ecosystem. But if you don't want to lock your code to a specific ecosystem, an independent language such as C++ or Rust is a better choice.
C++ is only independent on the surface, as all the big players seat at WG21, and it goes where their votes say it goes, plus what actually gets implemented into compilers (none of them is 100% ISO compliant, each one has minor compliance issues).
Same applies to C, stuff like C23 is decided by who gets to join WG14.
In both cases, someone has to buy the final standard from ISO.
I was thinking more about pragmatic issues, and Java is a good example of them. It's a widely used language, but it's also a huge failure.
25 years ago, Java was supposed to be the new general-purpose language you could use for everything. Universities rushed to teach it to everyone. There was a lot of initial success, but then Java started losing ground. The direction the language was going was not good for many applications. And then lawyers got involved, which didn't help.
C++ is a general-purpose language. It's widely used, because it's widely used. The language is good enough for many tasks, and you can probably find the libraries you need and people familiar with the language. If you work in a niche with no specific reasons to use a particular language, C++ is often a good choice.
Rust is not there yet, because it's a new language with limited library support. But it does have momentum. The biggest threat to Rust as a general-purpose language is probably async. When there are strong interests to develop the language and the ecosystem for specific applications, other niches often suffer.
Use C++ for writing a high performance library or a database engine.
Use Go or Java for writing a server.
Use C for writing a kernel module.
Use shell scripts for automation.
Use python for trying out ML ideas or heavier duty scripts.
Use Rust for ... I'm not quite sure what it's the right tool for yet. I suspect it's trying to become the right tool for all of the above and not succeeding much in practice.