[UPDATE: Sony Updated the post on the PlayStation Blog the PS5 will run way more than a hundred at launch but an "overwhelming majority" as said in the PS Blog update. No clear answer on whether it being placed on a compatibility list.]
The backwards compatibility news is not something you are going to like. Remember when everyone said backwards compatibility is essential now. In Sony's Road to PS5 video presentation (see above), not only was the presentation a disappointment but it shared bad news. Stated by Sony at 27:00 that the PS5 is expected to be backwards compatible with almost all of the top 100 played games on PS4 at launch (Mark Cerny). This can put not only the PS5 at a disadvantage but console gaming in general.