The compatibility percentage is still within the high 90s it seems. Including digital-only games (which are a significant majority), there have been over 4000 PS4 releases.
There are at least a few on here that I have that won't roll over to the PS5. I'm not getting a PS5 soon anyway, and I was planning on holding onto my PS4 Pro in the long run.
Lifetime Sales Predictions
Switch: 151 million (was 73, then 96, then 113 million, then 125 million, then 144 million)
PS5: 115 million (was 105 million) Xbox Series S/X: 57 million (was 60 million, then 67 million)
PS4: 120 mil (was 100 then 130 million, then 122 million) Xbox One: 51 mil (was 50 then 55 mil)
3DS: 75.5 mil (was 73, then 77 million)
"Let go your earthly tether, enter the void, empty and become wind." - Guru Laghima