Because of the nature of my job, I am at different Tech and Pharma/Biotech Campuses all the time.   I see what people make because I have access to all that information. 
STEM grads make a lot of money.  It's way more than you would think. I work in high Cost area, so my perspective is a little distorted.   But I was shocked at what a lowly " Scientist II" was making.  We're talking  past $120,000.
but.....I don't think it is the degree that matters.  If you're smart and have a good work ethic, you're going to do well. I can easily cross-reference with linkedin and see someone's educational background and job history.  The most successful people don't necessarily come from the best schools or the best companies.  I see a lot of people who have come from less prestigious companies and schools, but moved up really quickly.
Even at my own current job, being smart and hardworking get's you a lot farther than just having good grades and a degree.  Myself for example, I received a perfect job review rating, and I am recognized as a rising star in the company. I work for a huge multinational and prestigious company. I am not terribly smart, but I thrive in a high-stress environment, and I perform much better under the preasure of a deadline. I never go online at work, and I can stay focused for hours on end. I also work much faster than other people.  I guess I have a lot of "grit". If I can do well in this world, then I think that everyone can.