The fact that I'm a 21 year old drop out making nearly 100k because I sat in my mom's basement for a few years and studied software that interested me is pretty crazy.
Market price is market price. These companies are generating massive income. They are paying high wages (and colluding to avoid paying higher ones) because engineers are necessary to that.
The question you should ask during salary negotiations isn't, "Do I, based on my own value judgments and moral code, deserve this much money?" It's: "Are they paying me market price for my skills?"
If market price for your work is more money than you need or you believe you deserve, then take it and give it to somebody you think does deserve it. I promise you that if you let your employer keep the extra, they will not do anything better than you will with it.
Remember this is net rev, what they take in after paying everyone. Assuming the average employee makes $120K, and given that they can't exist long enough to make $1 without the engineers showing up, these companies should be willing to pay everyone up to 2-3x that
What's even crazier: owners of firms get paid millions or billions of dollars for doing much less than you do--literally nothing besides initially deciding to purchase shares, in large companies--merely because they acquired, one way or another, a big bundle of cash earlier in their history.
How do I properly quantify exactly how much value I'm adding to the company I work for and the world to possibly determine how much I'm precisely worth?
You should. I write code in another industry (HFT) and most people coming out of college are getting 400-500k bonuses or more after a year. We joke about how raw of a deal the average developer in SV is getting -- Google has roughly the same net profit/employee that we do (maybe even more), and all they're getting is chump change.
I both hate and admire you for that. One bonus like that is all I need to finish plans for good. I know talented programmers getting the equiv of $50k and I wish I could do something for them.
you aren't paid in proportion to your worth; you are only paid in proportion to your negotiating power. if 50 other people can produce the same worth for your employer, you're going to be paid a lot less than if you are the only one who can produce the same amount of worth.
don't take this as an argument that you are being paid "unfairly" - you're not. just see it this way - you are worth much more than that. set your career sights a lot higher because you deserve it.
What form of success here qualifies as "weak?"
If big tech companies are colluding to depress engineer wages, they're pretty obviously failing.
You're going to have to show your work here.