Manning signed:"A five-year deal for $90 million, or $18 million a year -- equal to what New England Patriots quarterback Tom Brady is making." This was current as of July 2011, so yeah.. he was due a lot more. As a Manning brothers fan, I think that while this was unfair, it had to be done to Peyton, the nature of his injuries is going to make it hard for him to ever play to his full potential again.
That being said, I do wish Luck.. well lots of luck in his endeavor to fill the shoes that Manning left behind. After all, it was his wins and the combined efforts of the team that helped build that stadium fans now plop their kiesters in.