To be fair (and leaning waaaaay over backwards) just "working hard" in and of itself is not a guarantee of success. Lots of people work very hard every day and bump into a ceiling WRT advancement. There has to be opportunity to succeed (and in college there is plenty of that). But, in the workforce there are lots of impediments to advancement. I remember when women were getting mainstreamed into the workforce and complaints of the "glass ceiling" were popularized. Funny thing is, most men had bumped into that same glass ceiling for decades with nary a whimper. Of course, back in that day there was a social contract between employer and employee that lasted (generally speaking) a full career. People did not bounce around every two or three years from company to company like they do now. But generally speaking again - that's being done because the opportunity to advance isn't in the current job - it's in the next job.
Just my 2¢.