Brady's salary was maneuvered brilliantly with the Patriots, by taking lump sums in select years and spreading smaller sums for the remainder. Tom Brady over his career has made his money, it was just paid differently. Let's be honest, this shows just how much smarter the Patriots are as an organization than the rest of the league.
The $75 million difference is also skewed. from 2000-2002 Brady was on a rookie contract based on being a 6th round pick. Peyton on the other hand, was already past that salary restriction. If you compare prime Brady (05' and on), you'll see Brady made $137.8m and Peyton $147.4m. Peyton made more, but it wasn't as much as you suggest. The key is how the payments were structured. But this wasn't meaning Brady took a huge discount in pay, he just got his salary loaded in select years to maneuver the salary cap.