Earlier quoted context omitted.
This isn't Arch Linux we're talking about, it's the presumably tested and released operating system for the most premium personal computing hardware in the world. I'm not saying you shouldn't back up your stuff but your expectation on user behavior is unrealistic to put it mildly.
I am not very experienced with Arch, but my impression is that it is actually more reliable when updating/upgrading then going to a new major MacOS release, which is an absolute disagrace given the fact that Apple can actually test their stuff on every single hardware model it is supposed to run. And no, my experience on general user behaviour is to expect no backup, but this isn't Auntie Ednas crocheting Facebook gr…
I used Arch briefly and this was not my experience, but at least in that community it's kind of expected that you understand this is a possibility and a tradeoff of running the OS.