That looks like it might be a worthwhile book. Thanks for the recommendation. I'm not "so certain that the probability of success is higher in the valley," but

That looks like it might be a worthwhile book. Thanks for the recommendation. I'm not "so certain that the probability of success is higher in the valley," but there are two main reasons I think there might be something to it: firstly the fact that people whose opinions I respect are saying it, and secondly the anecdotal-evidence-based but sensible conventional wisdom about meeting more relevant people (whether for funding, employees, advisors, bouncing around ideas, etc.) in the valley. I haven't noticed as much that "the majority of the people who say this have something to gain, directly or indirectly from this being promoted as fact," but maybe I haven't been paying enough attention. :-)