From experience, I highly doubt it was actually unrecoverable. I did something similar many times & all it takes is to read archlinux.org news section & apply .pacnew config diffs where needed. Arch is a bleeding edge distro constantly marching ahead; that's one of its primary advantages, so it's best to update regularly. That being said it is very much possible to not update for months, just requires a bit of extra care when you finally do due to the large number of accumulated changes.

I even did an online, in place switchover from SysV to systemd in 2011 and despite that being a scary amount of changes at once still got a working system.