From my experience in the industry, the model that Roose describes for banking very much applies for top management consulting as well.
What I'm seeing now is that Silicon Valley and Generation Y are breaking it – not to the degree that it doesn't work anymore at all, but diminishing the model's success of providing a massive competitive edge. In earlier days, the smartest, most ambitious people went into academia and public service. Later, they went into the financial services and management consulting. Now they're heading to tech companies, or (gasp) become entrepreneurs or freelancers.