It sucks to lose at a career gamble but, at least in Silicon Valley, most people who fail but keep trying, end up doing pretty well.
The current combination of risk-aversion and the focus on publications, tenure and positive results that permeates academia is antithetical to the uncertainty inherent in scientific research.
It seems to me that building new research institutions like YCR with a culture that resembles the one in tech which accepts and encourages risk-taking should be a priority if we are to continue to make progress in science.
It's easy to say that "more people" should take career risks. It's harder to be the person who's spent their entire life striving toward a Ph.D. in the field of study they love, and face the (very real) possibility that they'll get one shot and that's it.
Even if they can land at a Silicon Valley company (not as likely for biomedical researchers, BTW), that's not their dream. Their dream was to do groundbreaking scientific research. That's why they got their Ph.D. instead of a job in Silicon Valley.
I don't think Sam addressed the commenter's concerns at all.