It's hard to predict the future, and this forum is going to be very biased 
I think Rust does its job well enough that it managed to change "C/C++" into "C/C++/Rust". I can see it significantly replacing C for new projects.
Whether it will also displace C++ depends on interoperability with C++. There are major codebases like Qt and Unreal Engine that require C++, and Rust isn't established yet in GUIs and game development.
Currently, I don't see any language replacing Rust directly. Rust had a nearly a decade of growing its ecosystem and proving its usefulness and stability. Even if someone made a "Rust but better" language now, it may be hard to justify switching to an even newer language.
However, there are lots of use-cases where Rust is not necessary, because higher level GC languages are good enough. As computers get faster, the set of programs that need bare-metal performance shrinks, and set of programs fast-enough in any language grows. I can imagine other programming languages taking Rust's good parts like sum types, send/sync, and explicit ownership, but having a GC and other simplifications to make it easier to learn, and such languages can indirectly displace Rust for uses where Rust isn't necessary.