I'm sure Jak & Daxter (along with Ratchet & Clank and Sly Cooper) all ran at 30fps on PlayStation 2.
I think the simple answer as to why Naughty Dog are targeting 60fps for Uncharted 4 is because they are happy with their quality of the visuals. When your shadowing, lighting, draw distance, textures, shaders are all exactly how you want them and you have a ton of GPU resource left, you basically have two choices: a) your go faster, or b) you try to cram more in each frame.
Sometimes less is more, visually. If everything is already of high quality, and you're running up against the laws of diminishing returns, a higher framerate is probably the way to go. Sure you could maybe use that spare GPU time to make the shadows marginally better or use a better AA solution but if this is only detectable by people freezing the game and looking really closely a small bunch of pixels - which probably isn't how 99% of gamers experience the visuals - is it worth it?
As a gamer, I'd say not.