Except when it's not, and the answer is the maintainers [1].

[1] https://bugs.archlinux.org/index.php?do=details&task_id=5051... (hit this myself a couple days ago)

Nowadays, the reason why it broke is either you, or Systemd. But the reason why your system has systemd is that you didn't uninstall it.

Your system might have also broken because you didn't read the RSS feed, which warns of potentially breaking changes.

When in doubt, blame yourself. Or Alan.