It's about choices and possibilities.
Education surely allows more choices in future. I'd say the majority is studying for the degree rather than the knowledge. Better degree is more likely to get you better job.
In my country, the inequality between social classes and different region is so drastic, and considering how far we have come over decades, many people have this hope of finding a better position in society. In the ancient time and now, exam seems like the most equal way of competition for fame and power.
If we could live a easy life that doesn't require a high degree, like being a mechanic or running a small shop, maybe people would be less obsessed with exams.
The core is how economy and political system shaped our mindset. We have seen huge changes in the past decades, and I think there are more to come.