By top down, I'm referring to the top-down command structure of the NFL. The coach makes their guys do things. Players in the NFL are motivated by money, so there's less team cohesion, which requires a top-down command authority to get stuff down. That's why you sometimes see rivals on any given team fighting over who gets the ball: because that potential touchdown brings in extra money, per their contracts. Money changes how you do things.
In college, players are there because they want to be at that school. The coach is in command obviously, but there is a true team atmosphere. You're fighting for your school, which is akin to fighting for your country in an actual genuine righteous war. Coach tells them what to do, and they all work toward that goal. If you get a good coach (Pete Carroll at USC), you're going to have something closer to family that fights together. Money isn't a factor, but school pride, and pride in your team. The top-down formula generally doesn't work in college. See Lane Kiffin as an example of why top-down doesn't work at the uni level.
Notable exceptions to the top-down include the '72 Steelers. They were a true team. But that was when you had a real job and the NFL was your moonlighting job. I don't see much of that past the middle '70s in the NFL.