Hypothetical question:
If all these OS software was written in a memory safe language like say rust, would it be possible to get rid of these 'off by two' and 'out of bounds' error completely making the world a better place?
But please don't think of Rust (or anything else) as a silver bullet. If you are doing systems programming you are going to deal with unsafe code somewhat frequently. And, by not being exposed to this kind of programming often enough, it's possible that more errors will slip through the cracks.
Then there's a whole class of errors that cannot be prevented by memory safe languages. They cannot prevent crappy practices.
While Rust does solve some of the problems that C++ creates, there's no substitute for good programming and thorough testing.
That happens to be more a factor of not wanting to rebuild everything from scratch than anything else.
Go reference implementation is fully bootstrapped in Go.
D guys a few months ago ported their frontend to D.
C#, VB.NET and F# compilers are botstrapped nowadays. With .NET Native, maybe some other parts could eventually be re-written.
The OpenJDK gets less C++ with each release and there is the plan that when AOT lands, they will slowly migrate other parts to Java as well.
Of course trying to write an optimizer from scratch that beats LLVM or GCC backends is an herculean task, hence why most projects happen to use them as backends.