PC Games will always look superior playing multiplats because they are ports and they are not designed individually to make use of the full hardware of a specific console.
Exclusives won't always be behind and honestly I think 2-3 years from now once they get full understanding of the consoles, it will look as good if not better than any running PC games at the time (most PC exclusives don't look good at all). As I said earlier a few games already shown off for next gen of consoles look better than any high end PC game out right now, and those are multiplats not even exclusive and they are like a year from being finished.
Graphics can only get so good, there are diminishing returns each generation, there's a reason why the jump from PS2 to PS3 was far more impressive than PS3 to PS4 (even though it's still nice). Graphics can only get to a certain point before everything starts looking the same regardless of hardware, a face can only look so detailed, and that point is closing in fast.
I'm a PC guy btw, love my PC for mods/steam etc, so I'm not being biased in anyway just calling how I see it.