Reduce is a Lisp library that's still in active use from 1968, making it older than C itself. We can point to GNU Emacs as an ancient and venerable self-contained Lisp tortoise with more wrinkles than are finitely enumerable, and is in fact a hosted Lisp operating system. Pulling it apart and working with it is admittedly a treat even if I loathe it as a text editor. Mezzano is a modern Lisp OS that you can play with in a VM, and might give you an idea of why Lisp is such a great systems language.

In short: Lisp is semantic and geared towards a living system. The basic REPL is sh + cc + ld + db (and a few others) all in one. It's almost a little mind bending how nice these systems are put together, how cleanly they work. C is like pulling teeth in comparison.

I'm not even a fan of Lisp or sexpr languages. But it's the obvious heavyweight champion of longetivity and ultra-pragmatic service record... Yes, even in the systems domain.