X is being deprecated in favor of Wayland, the only way to not use it is to not use new versions of Linux.
NetworkManager replaced every other networking that came before it, DBus replaced configuration files/CLI tools/UNIX sockets, PolicyKit->polkit replaced standard Unix permissions (and before that PAM, which oddly still exists), filesystem standard changed (/sys/ and /run/ didn't used to be a thing), bluetooth changed, alsa -> pulseaudio -> pipewire. Most hardware and driver specific behavior seems to change, breaking whatever system files, configuration, modules, firmware, etc came before. Video subsystems seem to change like every 5 years.
And systemd isn't just "12 years old", it has been growing (like The Blob) for 12 years. It used to just be an init system. Now it's a network manager, a DNS resolver, a log manager, a credential manager, a login manager, a partition manager (yes, really), a container manager. resolv.conf -> systemd-resolv, fdisk -> systemd partition, syslog -> journald, netrc -> systemd credentials, login/controlkit -> logind, docker -> systemd.
Among the most serious changes is that now you literally have to use systemd for most graphical environments on Linux. To not use systemd, you have to use fake systemd replacement tools, because everything depends on systemd so much now. That's some serious churn.
NetworkManager replaced every other networking that came before it, DBus replaced configuration files/CLI tools/UNIX sockets, PolicyKit->polkit replaced standard Unix permissions (and before that PAM, which oddly still exists), filesystem standard changed (/sys/ and /run/ didn't used to be a thing), bluetooth changed, alsa -> pulseaudio -> pipewire. Most hardware and driver specific behavior seems to change, breaking whatever system files, configuration, modules, firmware, etc came before. Video subsystems seem to change like every 5 years.
And systemd isn't just "12 years old", it has been growing (like The Blob) for 12 years. It used to just be an init system. Now it's a network manager, a DNS resolver, a log manager, a credential manager, a login manager, a partition manager (yes, really), a container manager. resolv.conf -> systemd-resolv, fdisk -> systemd partition, syslog -> journald, netrc -> systemd credentials, login/controlkit -> logind, docker -> systemd.
Among the most serious changes is that now you literally have to use systemd for most graphical environments on Linux. To not use systemd, you have to use fake systemd replacement tools, because everything depends on systemd so much now. That's some serious churn.