It didn’t start in San Francisco. The modern electronics industry grew up near Stanford University, south of San Francisco in what is now known as Silicon Valley. After WWII there was an influx of students due to the GI Bill and to expand Stanford’s Engineering department land was leased to develop an industrial park for high tech companies. The first tenant was Varian (my husband’s employer) which later developed computerized gas chromatography. Stanford grads William Hewlett and David Packard also opened their first company there. In the same area were military bases that were working on electronic research. During the 50’s and 60’s other companies gravitated toward the valley and it’s labor pool. The first transistors using silicon in semiconductors came from a company in the valley and with the growth of the electronic industry silicon semiconductors took off.
Where there is a burgeoning electronics industry, a programming industry will follow as well as the internet related companies.
Steve Wozniak and Steve Jobs were locals who got their first jobs at HP and the game godfather Nolan Bushnell had immigrated from Utah to be a CA hippie when he moved to the valley and started Atari. By the 90’s it was almost the only place to be with the founding of E-Bay and YAHOO! as well as the internet bubble tht burst in 1999. BTW selling eggs on the internet was a bad idea.
San Francisco was the nearest big city and financial center where these start-up companies looked for venture capital. As in the case of many big cities, towns in the metro area identify themselves as the city. In 1970 the world might not know where Cupertino, Santa Clara and Palo Alto were but they did recognize San Francisco.