Actually, some are claiming Xbox is not really RDNA 2, but RDNA 1.9. Basicaly a custom RDNA 1 with RDNA 2 features, including Ray Tracing. But since A
Just a theory to answer your question. A what if!
Here's AMD roadmap!
As you can see RDNA 2 was always refered as not having total Ray Tracing capabilities, or at leat the power for it (selected lighting effects). That would only happen mixing RDNA 2 with the cloud... Something Microsoft can do easily!
Now what if Sony, not having the same infrastructure, used an ASIC, a bit Nvidia style, to complement RDNA 2, skipping the cloud?
A secret sauce.
As I said, just a Theory...
Full Scene realtime RT in an AAA game out of $400-$500 console!!! If so, everybody else has fucked up. LOL