I'm not so sure about Passer Ratings, but if you look at the QB's who took their teams to Conference Championship Games over the last two years (which I think is a better indicator of success...it's about winning, not Ratings), you find that seven QB's accomplished that feat (Brady did it x2). If you look at those seven QB's, two are measurably below the cap hit average (Brady and Luck), one is more or less on the line (Palmer) and four are measurably above the line (Newton, P. Manning, Rodgers and Wilson). So, no matter how you cut it, all those teams got what they paid for, with some paying a lot more than others.
If you look at the rest of the players above the line: E. Manning and Big Ben have at least delivered SB wins x2 in the past and have cashed in; Brees and Flacco cashed in as one hit wonders (more power to them!). The other four are laughing all the way to the bank: Romo got to the Divisional Round in 2014 and Smith in 2015; , Ryan was one and done in 2014 and didn't get to the playoffs this year; Rivers and Stafford didn't made the playoffs in either year.