Arch normally immediately updates to the latest version of every program

This is not true though. Arch packages new program versions as soon as they can - for popular stuff this happens quickly but not everything updates quickly. And when they do publish a new package it goes to the testing repo for a short time before being promoted to the stable repos. If there is a problem with the package that they notice it will be held back until it can be solved. There is not a huge amount of testing that is done here as that is very time consuming and Arch do not have enough man power for this. But they also do not release much broken things at all. I have seen other distros like ubuntu cause far more havoc with a broken update then Arch ever has.