I dig the way this handles multiple screen sizes instead of responsiveness, but my lifelong question continues to go unanswered: Why does the W3C and every CSS

I dig the way this handles multiple screen sizes instead of responsiveness, but my lifelong question continues to go unanswered: Why does the W3C and every CSS framework avoid making 'center' a thing? Yes, I know how to do it myself...I'm just saying that it has its place. Doesn't it?