The primary benefit of a top university/LAC is that, generally speaking, you are exposed to a group of more motivated more academically capable peers and professors, and your mind is shaped in a more intense academic crucible. The secondary benefit is that if you perform well you will have better access to certain professions (that can be very difficult to otherwise access) and to the top graduate programs.
The set of Universities and LACs that feed the top financial (investment banks, hedge funds, money management, etc) and strategic consulting firms as well as the top graduate schools (law, medicine, business, etc.) include the Ivies+ (Stanford, Duke, MIT, etc.) and the top LACs (Williams, Swarthmore, Amherst, etc.).
Every university/LAC has a bell curve of outcomes. The better the university/LAC the farther to the right the center of the bell curve will be. There will always be anecdotal evidence of success from a less selective university and of failure from a more selective university, because every bell curve has a left and right tail.