As of today, Kimmich and Hector are probably the only likely starters for Germany next summer who were on this Confed team, although Mario Gomez might have a hard time holding off the several forwards Germany has played this summer.* Germany was the youngest of the 8 teams in Russia. A lot could happen between now and next summer though, there are lots of possibilities between this team, the U21 team that also won a title this summer, and whatever is going on in Loew's head. In any event, it seems Spain and France are both loaded with great young superstars, but Germany seems to have more sheer numbers of talented young players coming out of the woodwork. One might conclude that the huge financial advantage the English clubs have tends to lead them to buy established talent, whereas the clubs in Germany, France, Spain have to focus more on developing talent in their academies. That's kind of a knee-jerk hot-take, but there may be something to it. Its well-known that the German DFB has been extremely focused on youth development for the past 15 years or so, having implemented a major overhaul of their club/academy system in the early 2000's.
* edit - and possibly Draxler