You misunderstand it, then. Arch is stable enough that (unless you're doing stupid things, like grabbing half of your system from the AUR) there will only be a breaking change every three years or so. Just set a cron job to update it for you and you have nothing to worry about. It was literally created for lazy system administrators, and it's only gotten better for them as time goes on.

if that were true their FAQ wouldn't tell you that broken packages weren't their responsibility.

I don't think that's true at all. If you use Ubuntu, broken packages are ultimately your responsibility unless you're paying for support from Canonical. In both Ubuntu and Arch Linux, changes will be handled carefully by the maintainers to try to avoid breakage where at all possible. The difference is basically that on Arch you're supposed to be able to handle basic sysadmin tasks yourself, which means that Arch Linux will ship breaking changes (with a mailing list warning) that require you to run a command or two yourself. Even with that qualifier, this is uncommon.

> on Arch you're supposed to be able to handle basic sysadmin tasks yourself

And the reason for this is because you realize the latest update killed virtualbox and you require it for your work so you need to be able to downgrade and pin the vbox application to a specific version.

Meanwhile, Ubuntu catches the problem and refuses to update the package until it's fixed. Therefore I never even realize there was a breaking update to vbox somewhere.

The difference being that Arch tells me when to tinker because it blew up again, Ubuntu allows me to choose when to tinker because it doesn't.

That faq doesn't make a claim about how frequent such things are.

In my experience it happens very rarely and is often quite easily resolved.

  >happens very rarely 
  >is often quite

Well you sure convinced me!