As i suspected. Most Sony's studios are working in 2 titles at the same time, following Insomniac's steps (Miles Morales + Ratchet & Clank).
Naughty Dog was working on TLOU2 and Factions. Now they are working on Factions and a new title.
Insomniac working on Spider-Man 2 and Ratchet & Clank.
Now Sony Santa Monica working in 2 games.
Sounds to me like Sony wants each studio to release something every 2 years at most.
Organic growth for sure!
Since they learn so much from each other, they probably watched whatever Insomniac was doing right and implemented in every studio, who knows? (this last part is just a guess obviously)