Does working for highly esteemed companies actually help build your career?

I'm a bit disturbed and annoyed by the popularity of the concept of social proof, and the fact that people assume its a good thing. I never see it discussed critically.

How is it not a mechanism of entrenched elitism? Wouldn't people born into higher socioeconomic circumstances inherently end up with a lot more "social proof" surrounding themselves simply as a result of the circles they've walked among? Doesn't this give rise to the "old boy network" and similar phenomena? Isn't it anti-meritocratic, anti-democratic, and generally something that hearkens back to the socialite mechanics of European aristocracies?

Is its popularity a sign that our own capitalist / democratic system is trending back in the direction of feudalism and aristocracy?