There are myriad industries, like car manufacturing, energy, finance, filmmaking, aerospace, health, etc. that involve huge amounts of technology, and whose leading players are based nowhere near Silicon Valley. But instead of going out and working in these industries to build something revolutionary, tens of thousands of world class programmers cluster in Silicon Valley, all talking to each other about how amazing and disruptive they are, while wasting their prime years blowing through VC money in startups chasing the latest ecommerce/chatbot/messaging/AI/blockchain fad, or as a cog in some tech giant's machine to turn customer data into advertising dollars.
It does have fashion, but it's not the biggest by any stretch.