> neither out of core tracing and sorting rays are feats of engineering

Presumably this statement based on your having shipped a production renderer that does these things?

> It has actually been done many times in both academics and commercial renderers from at least a decade ago

Academics, yes. Commercial--citation please? The only one I'm aware of is Weta's PantaRay, which is from only ~5 years ago (https://research.nvidia.com/publication/pantaray-fast-ray-tr...).