Not just garbage collection but also the way hardware work is done with languages that allow you to write one-to-one memory representations in order to be able to drive raw interfaces of hardware. A GC language almost always comes with a reference based type system that hides the very interfaces you'd like to access (fast) and adds deserialization overhead which has visible performance and battery life effects.

The other reason is C interoperation. All of the common systems rely on C. C is not just a programming language. Since 80s everybody designs systems on top of C. We ended up with OSes written in C that ship their tightly integrated C compiler that outputs binaries optimized for C's memory layout and primitives that the very same OS runs on silicon that's optimized to run C fast. C unfortunately became the meta-language of the low level APIs.

Go's interoperability with C is out of hell. Its green-thread scheduler doesn't play well with C. The foreign function interface is defined in the comments (!) of a source file and making CGo work on custom cross toolchains is full of hard to solve compiler errors.

Rust can operate at the same level as C easily and it has all the low level primitives. C interoperability is a core language function that's part of the syntax and standard library. It solves many gotchas of C without compromising speed.