I have bee saying this for awhile too. Even made a thread a few years back talking about Resolution benefits with regards to screen sizes.
Ideally, its best to have both. But I believe that framerate, effects and details should never be sacrificed for sharpness (which really is what resolution offers).
Like I would personally take 4k checkerboard rendering (which is like rendering at 1440p but better), with higher quality textures and effects across the board while running at a locked 60fps any and every day over a native 4k struggling to hit 30fps.
It just makes no sense to me. People should look at Ratchet, Horizon, GOW, Detroit and Spiderman (all games that have a really great checkerboarding implementation) and honestly tell me if they feel these games really need to look sharper. Its just makes no sense to me. Even more mind boggling to me is how much of a big deal is made abut resolution when they mass majority of PC gamers aren't even gaming at 4k. I mean if we are honest considering the amount of PC gamers that actually game at 4k/60fps its safe to say that specification is a niche in the PC world. Just a crazy ridiculous waste of resources.
I really, really, really, really hope that come next gen as standard Sony/MS offers a 4K.CB@60fps "performance" mode as standard where the only thing thats dropped is the resolution and then the framerate is increased. That will be my go to game mode for the entirety of that generation.