The more efficient versions compress the entire material stack in one, to exploit inherent redundancies, including albedo, normals, roughness etc. The main problem, as far as I can tell, is the increased GPU performance cost compared to block compression. Though recent research shows some versions are already pretty manageable on modern GPUs with ML acceleration: https://arxiv.org/abs/2506.06040
They cite 0.55ms per frame at 1080p on a recent Intel GPU. The budget for one frame at 60 FPS is 16.7ms, so the performance cost would be 3.3% of that. Though higher resolutions would be more expensive. But they mention there is room for performance improvements of their method.
The other problem is probably that it isn't very practical to ship multiple versions of the game (the old block compressed textures for lower end hardware without ML acceleration), so adoption may take a while.