Andy - Computers are a big part of the mix, and those tools are now easily accessible. To clarify: in Thiel's very beginning, computers were pretty limited. We used them from the beginning via Fred Collopy, another original collaborator who went on for his PhD in Decision Science - managing unimaginably large decisions with serious aid from computer modeling. We did Fourier Transforms (FFT) on impulse samples before 1980 and the number crunching took all night - literally we read the results the next morning. We used computers (Wang 600) before IBM or APPLE were in the personal computer business. So, we were ahead of winging it in the dark ages.
Your list addresses a few of the challenges. There are many more. Visionary unified engineering is rare and pure; I see Jim's work as that - one mind accumulating the questions and answers over tens of thousands of listening hours and iterations. That's a powerful thing.
One example of the contrary is the development of the CS2.7 by Warkwyn, among the best development engineering firms in the world with access to the Canadian National Resources Lab. It took them years of time and hundreds of thousands of dollars to develop the crossover for the 2.7 with the constant guidance and help of the team at Thiel. They have computers and resources to make your head spin. The tools are only part of the picture.