Comment by chuckadams

Yah I suppose I should have said "you just can't make any assumptions about the filesystem layout" instead. You can always assume shells have a symlink in /bin, and there's another for /usr/bin/env, and that's about it. Programs that assume the system follows the FHS tend to break on other distributions too, but certainly will on Nix. That's where we end up using containers and VMs, or whatever smoke and mirrors act NixOS does for Steam.