Your theory is still a theory. Only Naruto is the one closest to a sage because he's a Juubi Jin. Sasuke just has the Rinnegan, which doesn't even have the paths, and S06P chakra. Kakashi has S06P chakra and an incredibly hax ability. Grant this guy a tailed beast and he sits comfortably at the top of everything.You forget the concept of stress and the element of surprise in the story. Just because he didn't do it, doesn't mean he couldn't.
He can do multiple things at once, but even he has his limits.
My theory isn't really a theory. Naruto and Sasuke are basically Sages, Kakashi can't really compare to them. But I could give you a logical explanation as to why he can't be compared to them, which I did.