Three evident reasons below can explain this phenomenon.
First of all, studying in college or university offers more chances to improve expert knowledge. In high school, students just learn general knowledge and common sense which are necessary to live conveniently. However, in college, people can learn more specific and advanced knowledge which are hard to get from the high school education, and people can get the professional knowledge in their majors which would be required in their work places. For this reason, people may go to college, even though the tuition is so high.
Second, attending college or university gives new experiences to people. College or university students have more opportunities to meet new friends who used to live different hometowns, and they also have more chances to take extra school activities. In my case, I was a member of a group about helping disabled people, while I was a college student, and through several times of volunteer activities, I got to know what the real service was. If I had not attended the activities, I couldn’t realize that.
The third reason for attending college or university is some tips for career preparation. In college, people can learn new skill for careers with a lot of opportunities. It should be great opportunity to expose myself to having interaction between college and real working fields. That’s because each college or university has tons of information about jobs, and sometimes each major has some connections with some companies. Even if looking for more specific jobs, career preparation in college should be required.