Non, poweroff n'a pas toujours existé:

The toolsets have also grown and changed. There's now a poweroff command, not present in 1980s operating systems because the Central Processing Units on most contemporary machines had no way of controlling their power supplies.

et tu m'agaces franchement, aussi avec tes trolls répétés anti-GPL, anti-Red-Hat, anti-systemd, anti-TIGCC, …