30 years ago (actually 18) or not, players used to play for more than a paycheck. Yes; the league, with its rule changes, Machiavellian punishments, and season extensions has proven time and again that it's a business. Our own Sean Payton used the injury report and IR to stash players that he wanted fresh for certain games, or who he thought would be good for the team later. "He has a knee" became a running gag on this site. I think it's pretty obvious his players learned something from that as well.