On the other hand, he won a Super Bowl in just his second season. And also his fourth and fifth. Meaning that he should have had a lot of leverage very early on to negotiate his salary.
Just for fun, I took that list and divided the numbers by years played. This doesn't account for inflation, so I'm not pretending this is some kind of definitive answer. But it isn't meaningless either. Peyton Manning is sixth on the list, and he played earlier than the others. Mostly I thought it was interesting so I'm putting it out there. I quit after Carson Palmer because it started to get into WRs and such.
The number in parentheses is year played, and it's followed by the average salary per year:
Ryan (11) 20,295,455
Stafford: (10) 17,800,000
Roethlisberger (15) 14,948,292
Rodgers: (14) 14,698,393
Manning E: (15) 14,266,000
Manning, P: (18) 13,761,889
Brees (18) 13,451,833.33 (repeating of course)
Rivers: (15) 13,410,000
Smith, A: (14) 12,785,714
Brady (19) 11,977,590
Palmer: (15) 11,500,000