Personally if I were to attempt a project at this scale, I'd do so using a language I'm proficient in. There might be other reasons, but Rust & C++ really are different beasts.
Sounds like "Its hard, so it can't be done" to me.
There are plenty of people making good software in C++, how else would we have what we have. Sure, things get bloated and break over time, but thats not due to programmers not knowing C++, thats just what happens as a product evolves. New coders get brought in, focus shifts, understanding of the code based erodes. Its not that language, its the process.
