I was in sophomore year when I realized this. It's just more profitable to keep people ignorant.
It's the same reason why our government is controlled by private industry - from lobbyists to campaign donors. You can't get elected to a meaningful office without making deals to raise tens or even hundreds of millions of dollars. If a government official refuses to enact policy to help his or her benefactors, the sponsors will just give their money to someone else during the next election.
Another facet of our government many intelligent and wise people predicted is the military industry complex. This country has pretty much continuously been involved in military conflicts since the end of WWII. Our "defense" budget is astronomical. The whole system is completely fucked and there is nothing anyone can do about it.