It really does help create distinct eras and an air of unpredictability.
PS1: Crash, Spyro, Tomb Raider, FFVII, Metal Gear, Syphon Filter, Twisted Metal etc.
PS2: Jak & Daxter, Ratchet & Clank, Kingdom Hearts, Sly Cooper, Okami, God of War, SOCOM, Killzone, ICO, Shadow of the Colossus, etc.
PS3: Uncharted, Resistance, inFamous, The Last of Us, Heavy Rain, Demon's Souls, etc.
PS4: Spider-Man, Ghost of Tsushima, Death Stranding, Bloodborne, The Last Guardian, Astro Bot, Horizon, etc.
I love Sony's commitment to presenting new IP as their tentpole franchises. Nintendo and Microsoft dabble with new stuff, but their biggest games are extremely predictable. Sony has some predictable sequels too of course, but I think they're the best at busting out completely unexpected IP from their heavy hitter devs.
Can't wait to see what new IPs we get treated with on PS5! It's going to be so hype when we see Naughty Dog's first new IP since the PS3 era, or SSM's first new IP since the PS2 era.