As to evidence that he could be making a lot of money, I'm not all that familiar with Yudkowsky's accomplishments, but let's see... He can read, he can write, he can compute.
Many people can do that, making a lot of money is mostly luck. Do you think IQ correlates strongly with a lot of money? Maybe Mark Zuckerberg should be solving friendly AI then? Yudkowsky had this luck by finding the right mixture to get a lot of non-conformists to act like a cult and donate a lot of money. I'm not saying this is a cult or that the idea of risks from AI is wrong. But I am saying that the argument that the credibility of the idea is in and of itself important to a person is stronger in the case of Yudkowsky than Kurzweil. Kurzweil wants to live forever but has a broad spectrum of skills to make money. I don't see that being the case for Yudkowsky. He is not particularly charismatic or a good entrepreneur as far as I know.
Many people can do that, making a lot of money is mostly luck.
"Luck favors the prepared mind." -Louis Pasteur
Perhaps many people can do that, but for some reason many people don't do that. There's not that many students with SAT scores that are competitive enough to get into competitive colleges, for example. And those that do have the scores (or other factors in their favour) often end up reasonably well off in the finance department compared to their peers, statistically speaking.
And yes, there is some luck (aka factors we don't yet understa...
I just watched Transcendent Man about the singularity and Ray Kurzweil in particular. It's well-made, full-length, and includes the most popular criticisms of Kurzweil: that his prediction timeframes are driven by his own hope for immortality, that the timescale of his other predictions are too optimistic, that his predictions about the social outcomes of revolutionary technology are naively optimistic, and so on. Ben Goertzel and others get much face time.
You can rent or buy it on iTunes.