Combine this with what I have often said, that the mathematics of quant finance is straightforward if approached properly, and the following idea immediately suggests itself: Measure the ratio of typical salary in a quantitative field to the difficulty of the mathematics in that field. How much better off is the quant compared to the aeronautical engineer?
And does salary correlate with talent?
Quantifying the math difficulty, for the denominator in the ratio, is the hard part. Inspired by the kind of differential equations seen in many physical sciences as well as in finance we could start as follows.
Parabolic equations 5 points; elliptic 10; hyperbolic or mixed 15.
Four or fewer dimensions 5 points; five or more 10 points.
Linear no points; nonlinear 10 points.
The aero engineer might have a ratio of 5 (after rescaling by 1,000 to make the numbers neater), the quant a whopping 30.
In other words the aero engineer ought to be on the quant's salary and vice versa.