So... bigger focus on Streaming and expansion of Playstation Now content.
If i were to toss a bad bet now, i would say PS5 has Streaming Backwards Compatibility with all the Playstation console family. But only via streaming.
I think this makes a lot of sense to be honest. I think they change the entry point to streaming to mean owning a digital copy of the game rather than being forced to subscribe to PSNow though and PSNow can exist as a separate sub as an instant game collection.