Just so you the opposite is also true in 2008 the bottom 4 salary teams had records of 12-4, 11-5, 11-5, 2-14. Cowboys last year were in the bottom 5 salaries and as you stated they made the playoffs. The year the Giants won the super bowl they spent the least amount of salary in the NFL. The Giants go and spend like crazy last year spending more then any other team and the play 500 ball and don't make the playoffs. Raiders spent the most in 2008 where were they at.
Trust I have done it many times, there is no correlation to how much a team spends in a given year and their success. The only correlation I have ever been able to find is consistent spending over a period of time. Teams have never won by overspending in one season. Again, it is about spending consistently over a period of time. Case in point, come of the best teams in the NFL are in the top 10 salaries spent over the last three years - Cards, Pitt, Jets, Saints, Cowboys, Chargers, Dolphins. The only anomalies are the Redskins, Bears, and Bills. But then again that correlation only goes so far considering the Colts, Ravens, and Pats are all in the bottom 10 in spending the last three years. So the case can be made in those cases that as long as you spend money on a select few all stars, have good coaching, and good drafts to surround the all stars you can also win without overpaying. Two different formulas and two great arguments and examples for each.