All he would've needed was the support of RedHat management, after that everything falls into place: most Gnome contributors work for RedHat, so they can convince Gnome to follow a particular direction and hard-depend on systemd. Then most distributions are under pressure from their userbase to support Gnome (because of a legacy of politics and FUD about the KDE license, because a minimally-configurable environment is popular with the kind of large, inflexible organization that buys expensive support contracts, and because it's actually quite good software) and are therefore also obliged to hard-depend on systemd.
It's in RedHat's interest for software that's currently portable to FreeBSD or especially to Solaris to become tied to Linux. This wouldn't be the first time RedHat has adopted anti-opensource methods out of fear of Oracle - compare their policy of deliberately obfuscating the history of their kernel source.