Okay, now I have to defend PhD programs. You do not keep attending frat parties and act like you're 18. You attend classes, you teach, and you work in a lab. In fact, it's more like a job at the end. You go to lab every day, you do experiments, and at home, you are often reading technical papers or are writing up your data.
Most last more like 5 or 6 years, not eight. And people still party, but that's like any group of adults. The nice thing is that since everyone has their bachelor's, everyone is 21 or over, so we can actually go to bars and stuff.