As for any pair of [technology] and [hipster-fad].
What matters is whether they come out equipped to do what is needed. Those picking up Rust will graduate finding very few places to use it, and will have to pick up C++ as best they can under much more difficult conditions.
In my experience students who learn Rust first have a much easier time with C++. It's a more forgiving language for beginners, especially considering the tooling, which is top notch. I think most students coming out of university programs know or at least have been exposed to C++, so I don't know what you're trying to say about students graduating only knowing Rust.
You are saying that people who learned Rust in class have an easier time, later, using C++ than people who learned C++ in class?
That is absurd, unless in fact you are teaching C++ so badly that they first need to unlearn more than somebody with no experience with it needs to learn starting from zero.
Again, this has been true for literally every nascent language. Those picking up languages early in their lifecycle find fewer places to use it. As they gain momentum, it becomes easier.
This cycle has played out for C++, Java, Ruby, C#, Python, Golang… and everything else. What makes Rust a hipster fad, but these languages weren't?
Everything was a hipster fad. A few didn't fizzle, and matured. Not every hipster fad is taught instead of mature tooling.
Rust might not fizzle. It is too early to say. Ruby seems to be fizzling after what seemed like a promising start. C#, as a walled-garden language, does not even count.
What matters is whether they come out equipped to do what is needed. Those picking up Rust will graduate finding very few places to use it, and will have to pick up C++ as best they can under much more difficult conditions.