It's not because of cultural decline, it's because there's been a leveling of the playing field wherein competition has gotten a lot fiercer on two fronts: it's generally harder to get into elite colleges, and top-tier employers look at a broader range of schools than they used to. Put another way, being born into a wealthy family, attending Suburb Country Day and then spending a few years at boarding school is less of a tailwind for getting into Harvard than it used to be; and also, going to Harvard is less of a tailwind for getting a top-tier job than it used to be. So, the applicant pool to Harvard is less wealthy and more scrappy and pragmatic; and also, students once at Harvard make more practical decisions with regard to what they choose to study.
To give an example of an industry I know firsthand, as a (relatively) recent Goldman IBD alum I can tell you that there's been a profound shift in analyst recruiting over the last couple decades. 20 years ago, NESCAC alumni with humanities degrees were like half the analyst class and state school grads (other than Wharton) were an endangered species. Today the senior partner in your group might have a history degree from Williams, but few if any of the analysts do.
This is reflective of increased competition, not disenlightenment. And it's a good thing. The state school finance majors are better investment bankers and deserve the opportunity more.