I’m afraid I’m not well informed about the slow compile time issues, I only heard of them. I have a Ryzen 7 with 16 threads so I’m not the first who will feel this.
For what it’s worth. Rust is only 9 years old. While C/C++ are almost half a century old. C is 48, C++ is 35. Even F# is older than Rust with its 15 years. So, there is a ton of optimization that when into C/C++ compilers and run times. Rust can only get better at this point.
And depending how you use C++, the compile times also can get worse because of how modern languages aim to do more during their compile times in general these days.
I noticed it first with F# that the designers talked about wanting a very static and strong typed language because of the compile time advantages that they can gain from it. Like less bug prone code that shows its self only during run time. That’s the reason why there is no Null type a.k.a. the Billion Dollar mistake in Rust/F# for starters.