Textures can be scaled quite easily, at least when talking about 4k to 1k below that could cause GFX people to shout at you because automatic processes are bound to lose the wrong details. Meshes OTOH forget it.

Also I kinda was assuming 4x 1k to throw at a 4k screen as people were talking about home theatre screens. The "uses 4x VRAM" equation is for displaying 4x at 1/4th the resolution as opposed to 1x at 1x the resolution, whatever that resolution may be, and assuming you don't have a second set of close-up assets -- you can't just take LOD assets, being in the distance is a different thing than being in the forefront at a lower resolution: Foreground assets get way more visual attention, it's just how human perception works so you can't get away with auto-decimating and whatnot.