3delight also traces SDS and nurbs analitycally. In offline renderers geometry data constitutes to most of memory usage. Texture RAM usage is kept under a few GB by use of page-based cache.
Multiple gigabytes of geometry is a lot. That ends up working out to potentially dozens of hundreds of polygons per pixel. Even so the person I was replying to seemed to wonder why everything converted to polygons, which is because of a more holistic pragmatism.
Agree in general about geometry memory though: in high-end VFX, displacement is pretty much always used, so you have to dice down to micropoly for hero assets (unless they're far away or out of frustum).