I suppose they had to migrate the iPod OS team to the HomePod. Which is stupid because it pretends to be an iPhone SE running a special app on boot.
Honestly Apple needs to get it's shit together. Anyone with half a brain can see what Microsoft is up to with Windows 10 and what it means for the future, but Apple is unwilling and probably incapable of doing a major overhaul of their OS so they can unify iOS and macOS (and split iTunes into more efficient dedicated programs)