Probably more people pick up C++ for the first time, in any given week, than the total who use Rust in production today.
Rust also benefits from the limited historical baggage that comes with being new and incompatible. Unlike Java, which was in the same position, Rust adopted very few old mistakes, and especially unlike Java made few new ones. But as the language approaches industrial maturity (possibly within 10 years) early mistakes will become evident, and cruft will be seen to accumulate.
Rust designers have consciously chosen to keep the language's abstraction capacity limited, which makes it more approachable, but reduces what is possible to express in libraries. Libraries possible, even easy in C++ cannot be coded in Rust. The language will adopt more new, powerful features as it matures, losing some of its approachability and coherence. But Rust has already passed a key milestone: there is little risk, anymore, that it could "jump the shark".
The language is gunning for C++'s seat. Whether it becomes a viable alternative, industrially, is purely a numbers game: can it pick up users and uses fast enough? The libraries being coded in C++ today will never be callable from Rust.
Go proved that the world will make room for a less capable language (in Go's case, than Java) if it is simpler. Rust is much more capable than C, Go, or Java, and the world would certainly be a better place if everybody coding those switched to Rust. So, my prediction is that Rust and C++ will coexist for decades. The most ambitious work will continue to be done in C++, but a growing number will have their first industrial coding experience in Rust instead of C, and many will find no reason to graduate to C++.