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... Does the culture matter that much, or is the success a result of a confluence of other factors? Someone who appears to pride himself on his contrarian decision making like Dalio might see his culture as the defining differentiator responsible for his success.* I find it much more likely that Bridgewater's culture of open criticism (and elements of quantified self?) is like Zappos Holacracy and Valve's "no managers" manifestos, rather than a new set of principles to be brought down from on high. Each of these companies prides itself, and to some extent claims is the reason for its success, on a culture that was deliberately implemented instead of organically grown. After you see enough of these I feel you start to become "culture agnostic", and from my point of view I don't feel any of them has a causal relationship with profitability or productivity.
I've been wondering the same about Silicon Valley's obsession with culture. It seems cargo-cultish in so many ways - correlated but not necessarily causal, and almost certainly a victim of survivorship bias given the group think about culture among the startup crowd. Thiel's advice that your startup should be like a cult felt like that too.
But then I did a startup, and saw many others close hand, and realized that Thiel is right, at least initially it needs to be a cult. In the early stages pre-traction you simply don't have the bandwidth for deep philosophical disagreements among the team about fundamental product direction and strategy.
That part has got to be like a cult where everyone is on the same page and you can focus like a laser on developing your team's ability to work together and execute like a well-oiled machine. That capability is not to be taken for granted, and does not just happen, you have to make it happen with intent, and unless you get really lucky with initial hires who just gel right off the bat, every early startup goes through it.
One of the main pitfalls for early stage startups is emerging disagreements over product strategy and direction among the co-founders or leadership team. But this is exacerbated by slow execution, leaving more room and time for self-doubt and second-guessing. Thus developing execution capability early on is the most important strategy. Execution both helps you get to a point faster where you can see whether your product strategy is right or wrong, and helps you pivot faster if wrong. If you're going to deliberately implement a culture, make sure its focus is on execution ability. Joel Spolksky's "smart and gets things done" or PG's "relentlessly resourceful" should be a good enough template for 99% of startups out there.