Dark Sun's not coming.
After releasing only two books from January through August, the end of this year is very release-heavy for official D&D. They have to sell two boxed Starter Sets (mid Sep & early Oct), the two Forgotten Realms books (both releasing Nov 11th), and Eberron: Forge of the Artificer (early December).
That's two boxed sets and three hardcovers all releasing between Sep 16 - Dec 5, 2025, with just weeks between each release. That's already too many books to market effectively; I can understand them not trying to also put focus on MORE stuff coming after that.