Those are both usefully specific. There's no equivalent simpler preexisting single term that can be used in their place.

Unlike "groupset."

Well, there's "wheels." But chainset is the only succinct term available to express what would take a series of alternative words to describe.

Now, if only I knew exactly what a "chainset" includes.

Or what a "cockpit" (in the cycling sense) is, exactly, for that matter.