"Whenever I see a brilliant kid decide to join Goldman Sachs, McKinsey, or Google, I think to myself: a startup just died" What does mere dumb brilliance have

"Whenever I see a brilliant kid decide to join Goldman Sachs, McKinsey, or Google, I think to myself: a startup just died" What does mere dumb brilliance have to do with creating a successful startup? I thought it had more to do with stamina, discipline, luck, persistence, flexibility, hunger, vision etc. If that brilliant kid is more interested in working for a big company, maybe it just means that they were smart enough to realize that they weren't cut out for the ramen life.