I have no idea how much more common it is for German apartments is to have a parking spot linked to. Germans like to complain, so our drivers are of course all horrible, except myself of course, but I strongly suspect German drivers are indeed better than Americans. Our driving license requirements seem considerably stricter, and legal requirements to maintain a car also seem stricter. (Of course, this might depend on what state you're compared to in the US).
And of course, our streets and cities are built differently, too. And we tend to have better public transit options in places where you'd find a lot of apartments without parking spots.