There are many reasons why people attend college or university. I’ll try to explain why according to my experience.
First, in my country, Indonesia, many companies usually require people with minimum bachelor degree. If you don’t have bachelor degree, you won’t be able to go to next selection procedure. So, in this case, people attend university to get bachelor degree. Second, people with higher degree will have higher salary than people with lower degree. Of course, higher salary means better living. So, in this case, to get a better living, people attend university or college.
Third, people who attend university should meet new environment. This means he/she will has new friends. Friends can extend our inter-personal skill so people can extend their networks. So, in this case, people will have more friends by attending university.
Fourth, beside friends, people also meet their professors or lecturer. People may get recommendation from their professor to attend higher education.
Last, many companies sometime require specific skill or knowledge for their employee. College or university may offer those specific skills and knowledge. People may get more knowledge or sharpen their skills by attending courses offered in university. I think this last reason is the main reason why people attend university. As a matter of fact, this reason also encouraged me to attend university four years ago.
I agree that there are many other reasons, but in my experiences when I attended university and met my friends, these are several reasons why people (especially I and my friends) attend college or university.