None of this is correct. It's not my brain, I'm used to playing 30 FPS games and 60 FPS games, they are interchangeable for me.
The Last of Us is an issue to me. It's missing some major smoothing operations when it get's locked at 30 FPS, which was most likely removed or limited due to the targeted 60 FPS.
Do you have both versions available to you? I have said I tested both versions and switched between them ON THE FLY and they were essentially the same. There does seem to be some minor motion blur difference but the PS3 version was never high quality to begin with. It's still there on PS4 though.
I checked because I absolutely thought the same thing you did. Playing games on PC, I'm experienced with the spectrum of frame rates, and I thought the PS3 version was smoother than what I was seeing when switched to 30 on PS4. I didn't even think the input lag is close to that.
Switching directly from the PS4 60 mode straight to the PS3's 30 has the exact same effect. It feels like utter garbage for a little while, then you get used to it.
But it's GAF, and why would you care about empirical evidence when you have "feelings" and rely on 100% accurate human memory.
Even the Vita Remote Play could introduce some extra blur from the transmission. I suppose it all matters at 30.
In general though I agree that they should have added a better motion blur to 30, like Watch Dogs.