Author here. This is the case with *nix but doesn't need to be. As far as I'm aware, it's quite common in microkernel-based OSes to implement even ELF loading,

Author here. This is the case with *nix but doesn't need to be. As far as I'm aware, it's quite common in microkernel-based OSes to implement even ELF loading, dynamic linking, etc. inside system libraries loaded inside the process creating the new process. So the parent process basically constructs the child process, which means you could easily design an OS such that the parent needs access to the library files, but the child doesn't.