I live in a relatively overpriced place, and when I tell my friends from back east, or even the midwest their mouths salivate at the amount of money a normal Entry-level worker makes. $12/hr is a god send in most other locales. Here, in the Bay Area, it amounts to little under what I need to pay my half of the rent. Rents are higher, Gas is pricier, and even public transit is a chunk of budget overall.
I think that when you look at the working world as a whole, you see that most salaries aren't what they used to be; and aren't what they ought to be. Yes, trading fake bundles makes you millions of dollars while swinging a hammer only makes you 30-40 bucks a day. That's what makes the Wisconsin protests that much more poignant. Workers Unions have supported the backbone of my family for generations. My father was an Electrician, my Grandfather an Operator Engineer, and my Brother is a Sheet Metal worker. Trade work is good work. My grandfather used to say "The best view of the City is on a crane being raised to the next working platform."
It's not glamorous work. In fact, you go much longer without work than you do with it. However, in a horribly sloped world, somehow your salary determines who you are as a person. The admiration of money is the root of all evil. The moment we let money govern who we are as a person is the moment that we become wage zombies.
Now, For the actual question's answer. I believe that yes, it should be proportional to the amount of work done. However, I'm also a realist who understands that was never and will never be the case. People are always going to make up bullshit jobs that are basically "File twelve of these forms, and then fax them. Congrats, here's a $50,000 a year salary for your 4 years in college and your liberal arts degree".
At no point in history are salaries more skewered than today in this day and age. And that's fine. Granted, If you offered me the same job I'd relish at the chance to live comfortably and support my family and have such a shitty job that I could complain about 'all the paper cuts' or 'all the break rooms smell like fish'. Is it what I want to do? Hell no. I filed papers for a living, I hated it so much so they laid me and seven other people off just to save 200,000 grand a year. Their company, their prerogative. But I didn't do it because I was interested in being a paper jockey for the rest of my life. I did it because I had to pay bills, to keep my family clothed, fed, and secure for that month. It's not my life's primary objective.
I'm a writer. That's what I do with my life. I dabble in the arts and music, but my primary life's motivation is the fabrication and implementation of an article, novella, or a short story. I know it won't make me much money, so I take jobs on the side. It's an arduous career that is probably going to be the death of me, but you know what? At least at the party I won't have to say 'oh, I just push grants through for a living. It consumes 90% of my time, It's the most arduous job I've had in my life. And it's probably the most frustrating profession, but at least I can go home and buy that vintage 1910 Art Deco lamp for my home's entryway.'