A better analogy is Ivy League colleges. If you graduate from an Ivy League college (or publish in a prestigious journal) others view that as a signal of your

A better analogy is Ivy League colleges. If you graduate from an Ivy League college (or publish in a prestigious journal) others view that as a signal of your qualifications and that can open up careers that require that the box be checked. As such, people are willing to pay a lot of money to go to an Ivy League college (or publish in Nature). And the "system" has a vested interest in keeping that gateway in place, because the people that passed that gateway years before you, don't want to see it go away as it would reduce their own status.