I think Bowling for Soup has it right, high school doesn’t end when you graduate.
People still fall into the same categories, they just have different effects on your life. The high school portion of things had things confined to a smaller microcosm. Once you’re out in the real world, it’s like the Petri dish experiment that was high school outgrew its confinement.
Cliques are still a thing. And, if you’re not in the right one, society continues to frown upon you. Jocks are still jocks. Cheerleaders are now trophy wives. Nerds may be the only group that really excelled with something. Instead of getting swirlies and wedgies, the jocks now look to them to help run their businesses and 401Ks. It’s even mainstream to be geeky at this rate – look at the Steve Jobs and Mark Zuckerberg. Even presidential campaigns are similar to those for Senior Class President or President of the Student Council. It all boils down to who has the most money and who can get their word out there on the largest platform, flaunting the signs with the most visual appeal and catchy slogans.