Much has been made recently about the future and potential decline of football, a healthy debate stirring again after the eye-opening early retirements this month by players like Patrick Willis, Chris Borland, Jason Worilds and Jake Locker. But Sunday's veteran combine hammered home an important counterpoint, that for every player who decides to hang it up early, there will be a dozen others clawing at the NFL's door, doing whatever they can to get a shot.