The demo is admittedly a rube goldberg machine, but that's because this was the first time it is possible. It will get more integrated over time. And just like normal rust code, you can make it as abstract or concrete as you want. But at least you have the tools to do so.

That's one of the nice things about the rust ecosystem, you can drill down and do what you want. There is std::arch, which is platform specific, there is asm support, you can do things like replace the allocator and panic handler, etc. And with features coming like externally implemented items, it will be even more flexible to target what layer of abstraction you want