As another counter, Rust has never claimed to have "supplanted" C++. So holding it to that standard is holding it to a non-goal for itself in the first place.
tl;dr - Rust wants to be a foundational language of the computing stack and holding it to the standard of being bootstrapped, instead of relying on another language, is a reasonable critique.
Clearly Rust the language and the associated organization would not make that claim. Particularly where supplanted is a past tense verb and indicates that it is a completed project.
However, despite overblown complaints about the RESF, the community both in commentary and in practice has been extremely vocal that any language that does not have Rust’s memory safety model is not suitable for any new project or further use in existing projects. And while the RIIR meme is for the most part a message board strawman, again, the community surrounding Rust is busy reimplementing coreutils in Linux, putting Rust in the kernel, and rewriting the userland executables that most Linux workflows are based around (ripgrep being the most successful in this group).
It is clear that Rust, the community of users (if not the language as an independent entity) clearly wants to supplant both C and C++ at all levels of the computing stack. The push for Rust in the Linux kernel is enough evidence to support the concept at the most pervasive level.
Continuous references to wide spread adoption and endorsements by ‘big tech’ is used to frame Rust as the only viable option going forward. Blog posts, Reddit threads, and board comments all routinely take the stance that memory-safety (as defined by Rust) is ‘table stakes’ for any development occuring in current year.
It feels disingenuous to pretend that Rust is not trying to become the industry standard language in the way C and C++ is today and has been for multiple decades. And given that aim, I think talking about Rust, as the name for both the language and its community of users and supporters, is working to supplant C and C++.
Given all that, I find it fair to discuss the fact that while busy trying to maneuver itself into every space in the tech industry (from embedded all the way up to the front end for web web apps) and find some success in doing so Rust is still reliant on C++ infrastructure particularly for compilation. I was responding to a pair of comments about the desire to see languages that want to be the bedrock of the computing stack bootstrapped. I think Rust absolutely wants to be such a bedrock language and as such, I don’t think wanting it to be bootstrapped and not reliant on the C++ it want to replace is an unreasonable standard to hold the language to.
You see it all over the place, not the point of Rust core team, but certainly from the kind of posts that gave origin to Rust Freedom Force memes.