The thing that's missing from almost all discussions of making a "Silicon Valley" somewhere else is what I think is the key to the original Silicon Valley's suc

The thing that's missing from almost all discussions of making a "Silicon Valley" somewhere else is what I think is the key to the original Silicon Valley's success: intergenerational investment. That is, a bunch of guys hit it big on semiconductors in the mid 20th century, and instead of just buying boats and joining the country club, these people set aside a portion of their fortunes to invest in the tech-related businesses of the generation that followed. And, crucially, without extracting onerous terms from those investments. That established a culture of relatively permissive angel investment that encouraged innovation. Trying to get a startup off the ground in most other places it too hard because raising seed money is too hard, and even if you raise seed money, raising a series A is too hard, and so on. To make a Silicon Valley, you have to seed the ecosystem with an initial generation of successful entrepreneurs who are wiling to adopt the ethos of the SV angel investor, then provide an investment infrastructure to make sure that promising startups don't die on the vine. And, as many others have pointed out, an open spigot of government money was necessary for the original SV to develop, so that's probably necessary for any copycat.