It'll happen. Previously, we had texture tech that permitted us to really only tile a few textures on the landscape, and the blending was very gradual, which doesn't work well for most texture changes needed for a city. Which meant that we needed 3D objects for sidewalks, and a ton of decals, and all sorts of inefficient things, to make the ground look remotely OK.
The new landscape texturing system had been in the works for a while, so we were waiting on that to do any major work, and then it took a while to do enough work to be presentable. But we're on the way now with landscape that can be more individually detailed and controlled, we can get rid of the very short 3D meshes like sidewalks, or hundreds of decals, which helps perf while also looking better. It's a big win overall.
But it takes time to execute on everything, and we're still working mostly on GD. CC and GH burn my eyes now, in comparison to GD, and they will be updated.