What you been describing is not 3D models and meshes, which is what takes up the majority of the hard drive space.
My brother in christ, what the fuck do you think i’ve been describing then? I even linked an example of how the 3d model itself, the geometry, the mesh, occupies less disk space than the actual textures
For comparison, this Damaged Helmet in gltf format (which you can see on your browser here) has 15k triangles, a .bin file (the actual 3D geometry) of 545kb and roughly 3MB of textures - The Default_albedo.jpg is the “actual color” and it alone is larger than the .bin + .gltf, at 914kb.
What I see is that you don’t understand how procedural generation works. As is today, how do you think planetary terrain is generated? That it is all saved as a file that is read from your computer/PC? That you could load up a “planetXYZ.file” externally to edit it? That the terrain mesh is this huge file with all sorts of hills and plains that you could import/export and load in Blender?