Nanite has already a good compression system where even millions of polygons do not take much space compared to 4k normal maps for example and they already said it will improve. The problem is real for developers at the moment where you need to have different versions of the same asset. I also expect a big evolution around geometry, similar to what happened to textures over the years, people will find smart ways to add detail. It’s just too soon to judge right now, but it looks promessing to me.