Sony announces that the "overwhelming majority of the 4,000+ PS4 titles" will be playable on #PS5
— Nibel (@Nibellion) March 20, 2020
PS4 games will run at a boosted frequency meaning possible higher resolutions + frame rates (evaluated on a title-per-title basis)https://t.co/2X6rnXHKnn pic.twitter.com/NOIdSsXJ42
more you can read at https://blog.us.playstation.com/2020/03/18/unveiling-new-details-of-playstation-5-hardware-technical-specs/
and https://www.vgchartz.com/article/442838/sony-overwhelming-majority-of-ps4-games-will-be-playable-on-ps5/
I think indeed when it comes to communication and Marketing Sony is a little bit behind compared to when they announce PS4 back in 2013, probably because they just recently changing their company structure and many policy has change.