Duh, of course they were less common, because unlike castles, they were more expensive to build, maintain and garrison, thus only the super rich, and the emerging more centralized states could afford them.Star forts were just, overall, not super common compared to the high middle ages castle mania, but military and administrative power still tended to be linked in the early modern period.
Also the change of warfare and the improvement of general security situation led to the nobility moving away from castles to various other forms of dwelling (great house, mansion, palace, country house, or in the Alps, ansitz) even at the countryside, which were both more elaborate, and had minimal to none military value, outside of being able to fend off some bandits.