For a long time, I've been dubious about "rationality is winning". While it protects against one dangerous line of thought (I was right! It's just that the universe didn't cooperate), it fails to mention a time scale-- sometimes you lose before you win. And sometimes you wander around for a while with no apparent purpose, and then you find something unlikely and valuable.
Pratchett's lecture includes a description of his early life, and I don't think any rational person or any rational parent would have seen his early life as any sort of sensible goal-seeking, or likely to lead to winning in any sense.
Pratchett was a fairly bad student, though he did better when he had less competition. He read all the bound volumes of Punch (the major British satirical magazine), and learned from that classic.
He became a reporter for a local newspaper, a job with modest status and low salary. (In one of his novels, he mentions the voracious appetite of a newspaper-- it's got to have news every day. Somehow, this seemed more intensely true than the large number of other sensible things he said in his books. Looks like I was on to something.)
It seems to me that LW-style rationality would have had him working on being a better student and looking for ways to make more money early on, and he probably wouldn't have written Discworld.
On the other hand, Eliezer is doing quite well, and on yet another and possibly gripping hand, I doubt that going for increasing the probability of success would have started with "think really hard about existential risks".