Further, it wasn't even a hard dependency. You're really not understanding components and APIs.
> This forced other distros to either switch to systemd or drop support for GNOME.
No, again entirely incorrect. GNOME runs without systemd. A few distributions worked on ensuring GNOME runs without it. It took a while to make that happen, so for a bit some distributions needed to keep some components back. But still: you're talking about systemd while it was an interaction of a few components. Systemd consists of loads of bits.
GNOME _runs_ on distributions without systemd! It took work to make that happen, we coordinated to ensure the problems would be solved.
> I suspect that had Red Hat employees not added hard dependencies on systemd to any other software, that no distributions other than Fedora and RHEL and its clones would require it.
Again, you're so incorrect it's not funny. Arch was really quick to switch to systemd. I help out with Mageia, they really wanted to switch as well, but it took (volunteer) time to make it happen. Opensuse took a while, but still, they would've switched.
The only unique ones were Ubuntu (political crap) and Debian (partly due to political influence by Ubuntu).
Systemd was selected on merit by loads of distributions, not this conspiracy thing you're pretending it to be.