They have an ungodly amount of IP in the video game space that they don't use. Some only got two games or were based around fads or hardware so it makes sense to leave them in the past or at least only port them without a new installment or remake.
Here are some Sony IPs that don't need to be dormant or dead, even if it means changing studios or directors/producers.
Twisted Metal, Ape Escape
Jak & Dakter, Sly Cooper, Killzone
Resistance, Infamous
Not to mention even something like Everybody's Golf that is approaching or in dormant status. LittleBigPlanet could use a 4th numbered game or a Sackboy 2.
In the movie and tv space, I kind of get it. They don't have the flagship IPs that Warner Bros. and Disney have.
Also, a great way to capitalize on their IP is PlayStation All-Stars Battle Royale 2, done better this time. Remove the forced Super Moves needed for a KO and bring back some characters in addition to adding the large amount created since the game (Joel & Ellie, Aloy, etc.)
Lifetime Sales Predictions
Switch: 161 million (was 73 million, then 96 million, then 113 million, then 125 million, then 144 million, then 151 million, then 156 million)
PS5: 115 million (was 105 million) Xbox Series S/X: 48 million (was 60 million, then 67 million, then 57 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