if you don’t keep a rolling release up-to-date regularly (like once a week), packages start to break.
Those are packaging bugs then. With proper packaging everything updates seamslessly. Outside of SteamOS I’m not a user of Arch-derived distributions but I am a user of openSUSE TW which is a rolling release and I have one old notebook for a specific task I need to do maybe twice a year and updating was never a problem and installing a package triggers updating all affected dependencies.