I agree those are downsides. But I think memory safety matters more in the problem space where c++ is relevant. I understand that's debatable, but I think the historical evidence suggests that it is impossible to write memory-safe c++ code beyond a fairly low complexity threshold.
Indeed, however memory-safe c++ isn't on the top list of what makes GPGPU, HPC/HFT, LLVM/GCC relevant in the industry, as such, those ecosystems won't be jumping into Rust anytime soon.
Some recent examples, Apple recently added support for using Metal from C++ instead of Swift secure bindings, Android now supports Rust at the OEM layer, no roadmap for NDK/AGK support for anything beyond C and C++, Azure Sphere is "secure" yet SDK is all about C and C++ (no Rust plans), Khronos API ecosystem is all about C and C++, CUDA,....
Agreed the spaces you’ve enumerated make sense for c/c++ still because trading off memory safety is a sensible engineering decision given the current state of things. Unfortunately security vulns can still sneak in there though :/
