dnf is a large and complex tool to manage a format that has miles of backwards compatibility (and, for extra inconsistent fun, random cases of incompatibility, since they forcibly broke spec at some point, without changing the extension of rpm, so while there's the expectation of compatibility, many old packages just won't work at all and you'll have very little clue as to why unless you're familiar with the history of the format), and has a lot more to it than pacman.
I'm not talking about the workflow for an end-user: Valve is definitely not going to force people to run terminal commands to update their systems. While pacman's update workflow is way simpler than dnf's, it's just not relevant here.
I was primarily talking about the complexity of the tool itself, of updates, and also the complexity of packaging. Arch is a packager's distro, and much of the foundation Arch is built on is the Crux-style "as simple as possible" mindset. There's much less that can go wrong when you're doing much less with much smaller tools.
I'm not hating on dnf or rpm, here, for the record. They're fine tools for their use cases.
