Because Arch makes you do everything, the answer to why it broke is always you.
There was an unofficial motto to that effect at one time.
There was an unofficial motto to that effect at one time.
[1] https://bugs.archlinux.org/index.php?do=details&task_id=5051... (hit this myself a couple days ago)
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.