Every year, rookies find that once they enter the NFL, their previously elite skill set in college is - at best - par for the course on an NFL team. As a matter of principle, NFL players are bigger, faster, stronger, and more talented than college players because the NFL assembles only the most elite athletes they can find.
Which is why NFL teams are obsessed with athleticism over almost anything else, and which is why we as fans pore over 40-yard dash times and short shuttle times so much. You can teach most players to recognize when a defense is in man or zone, but you cannot teach a player to outrun a faster opponent.