There is no evidence that he could get a lot of money differently.
I'm not all that familiar with Yudkowsky's accomplishments, but let's see... He can read, he can write, he can compute. And from what I can tell, he can do all of these things rather well. They may seem basic skills, but it's no coincidence that they make up the three constituent parts of most modern academic standardized tests (GRE, SAT, ACT, etc.). And very few people bother to actually master those skills, or to keep them sharp.
He can bring people together and shape communities (e.g. sl4.org, SIAI, lesswrong). He can do original research. He can synthesize information. He has highly developed skills of elocution and is very good at methodically picking apart people's flawed arguments, while defending his own comparatively sound ones (look him up on bloggingheads.tv). He can popularize esoteric and implausible-sounding ideas.
This is likely not an exhaustive list, but it wouldn't be out of the question to monetize even a lesser subset of these skills, if he was so inclined. And if he was really desperate, he could peruse the Optimal Employment thread for inspiration.
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.