Your comment that Java and Rust don't overlap is valid, but going on to discuss how you're going to keep using C++ and Python, and how Unreal Engine uses C++, is wildly irrelevant.
Rust isn't going to replace Java, but it may supplant Java in a lot of fields where one wants both memory safety and an OO language with high performance. No one is (rationally) suggesting that Rust will replace every language.
The tone of your post, however, makes it sound as though you have something against Rust, and that you're more interested in pointing out all the things it's not good at, or shouldn't be used for, rather than contributing to a constructive discussion.
> I also pointed out that Rust has to win the mindshare of C++ programmers first, before even reaching other ecosystems
Not entirely true; Rust is an alternative to C++, but it's vastly more accessible to people who've used other languages like Java, Python, Ruby, and so on, where you get types, OO, and memory safety. Instead of simply resulting in a 1:1 replacement of C++ with Rust, it may result in a minimal reduction in C++ programming and a notable increase in Rust programming which would have been done in another safe OO language instead, but at dramatically worse performance.
Small clarification — Rust very deliberately does not do OO. It has features that look sort of like OO from a syntactic standpoint, but being object oriented is not a design goal for Rust.
Rust isn't going to replace Java, but it may supplant Java in a lot of fields where one wants both memory safety and an OO language with high performance. No one is (rationally) suggesting that Rust will replace every language.
The tone of your post, however, makes it sound as though you have something against Rust, and that you're more interested in pointing out all the things it's not good at, or shouldn't be used for, rather than contributing to a constructive discussion.
> I also pointed out that Rust has to win the mindshare of C++ programmers first, before even reaching other ecosystems
Not entirely true; Rust is an alternative to C++, but it's vastly more accessible to people who've used other languages like Java, Python, Ruby, and so on, where you get types, OO, and memory safety. Instead of simply resulting in a 1:1 replacement of C++ with Rust, it may result in a minimal reduction in C++ programming and a notable increase in Rust programming which would have been done in another safe OO language instead, but at dramatically worse performance.