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Why do you need to rewrite them? Rust can call C++ code, just like Java and Python can. (I note you list Python libraries like Tensorflow and PyTorch as C++, which is accurate because they're written in C++, but they're certainly heavily used from a non-C++ language.)
Rust definitely makes sense anywhere you are currently using C/C++ or Python/Ruby. Java is somewhat of a special case though, especially the Big Data ecosystem. Much of the fastest and most important Java tools are written in pure Java (or other JVM language) and as such can't be called from Rust in a reasonable way. Writing Big Data code in Rust is certainly possible from a performance perspective but is an uphill b…
Rust isn't aiming to displace Java. They're two different levels of abstraction. It's the same with Python. Rust isn't aiming to displace Python just as Java isn't aiming to displace Python either.
Rust one day could displace C++, but the odds are low, because in response to Rust C++ has stepped up its game and has changed as a language drastically. Most modern C++ features are concepts from Rust.