The list in the Linux desktop world is honestly pretty long and could be extended at will. Some examples:
Wayland, GNOME 3, KDE Plasma, Nvidia drivers, PulseAudio, DBus
Two of the three components in your list that are mearly mandatory came from the same engineer. Why we do we keep accepting his code?
FWIW, the desktop world is less important and I run Linux as a desktop. The nightmares I get from systemd are all about my servers. If we could have left servers alone, people like me wouldn't even have cared. As it is, I have to get out the kid gloves when I'm dealing with my service platform because Bad Decisions are now system standard.
Fedora has been defaulting to Wayland on fresh installs for at least two or three releases and generally it’s working okish. There’s still a lot of software lacking proper wayland support, though.
Perhaps it's just me but I haven't found an xorg problem in my life that's fixed in wayland but I've had a few problems in wayland that don't exist in xorg. My display needs are rudimentary though, so perhaps I'm not the target audience.
Putting wayland aside... is exactly what I've done. I don't need wayland, so I don't use it. With systemd, not only do many of us have problems but we don't really have a choice. I could run my world on Slackware but then I'd be a SPOF (much like systemd) and that's a bad way to build architecture.
Sure, you can use XWayland and just call it a day, but that doesn't really help.
The reality is that exactly due to the enormous legacy baggage of the "X ecosystem" it's not easy to just switch "to Wayland". GTK, Qt, and (again, due to the required hacks) all major apps (eg. Firefox) have to do serious work (as in finally implement something sane, now that it's an option) to work.
DBus is okay. Though bus1 might be an improvement, and having it in kernel would be a bit more efficient (zero copy, better security, etc).