- Gnome started to depend on systemd features. Now non-systemd systems become second class citizens.
- You used to be able to freely swap out window managers, taskbars, and so on, because everything was working with common standards. In the modern world, everything is integrated in your wayland compositor, and if you want to change the way window decorations look, you will also have to change everything else. Systemd is similar, it wants to take over so many responsibilities (task scheduling, DNS, session management), and if you want to swap out one part it is going to be difficult.
- Pulseaudio, NetworkManager, Polkit: Written in the same spirit, in part from the same people. Work great if everything works as expected, if they break it is a nightmare to figure out why. But code depends on them, so they become de facto standard on desktop linux.