Earlier quoted context omitted.
Part of the reason is that systemd has absorbed functionality of a number of additional pieces of software, to the point that they are no longer maintained discretely - udev being the best example. Another part of the reason is that Red Hat forcibly landed systemd in Fedora and then RHEL7, and RH is an elephant on the scale of Linux development.
So RedHat's choices impact Debian/Ubuntu, Arch, and SUSE so much? Honest question; I don't know the details. Or are you saying that distros rely on other components that are simply not feasible (maintained) anymore, so they have no choice? Just seems like if it's as bad as so many say, it just doesn't make sense for all these distros to blindly go along. Even the GNOME lockin doesn't seem like it'd explain it.
Canonical revenue is 67 million according to wikipedia, by contrast Red Hat is 1.5 billion. That is 3 extra zeros (and even then it is almost 1/100 of Microsoft's revenue).