let me walk u guys through this..
loving what you do=you being one of the best at what you do (most of the time, b/c you dont mind putting in the extra effort)
you being the best at what you do=being the cream of the crop and standing out
standing out (+ a little bit of luck +getting in with the ole boy's club and playing golf on sunday with them+ NOT being socially awkward+selling yourself to prove your the right man for the job)=superior position than co-workers
superior position=more income
*BUT the only thing i would add is that MOST engineers can get away with just getting a bachelors, whereas most b.a,b.sc's,b.commerce are a dime a dozen and graduate school (phd's,mba's) is necessary in order to further your career, but if you really love what you do it it wont matter anyways....(multiple degrees is also good!)