Now that I've found them, let me ask again: why aren't these numbers featured more prominently in election coverage?

This is really, I think, a question of the culture of election reporting, which varies widely from country to country.

I've noticed that in UK election coverage, for example, there is enormous emphasis placed on "swing" (percentage change from one party to another...reported in these German elections, but less prominently; and even less prominently reported, at least on election night, in the U.S.), as well as what the British somewhat misleading call "majority" (which we in the U.S. would call margin of victory) in each constituency.