I thought things got started in silicon valley because it was cheap with Stanford nearby. Then hardware slowly changed to software. As things grew people moved to San Francisco to enjoy life of the big city and still be close silicon valley. Microsoft moved to Seattle because it was Gates's home. And Nintendo was there because Seattle was closer to Japan. Microsoft grew and created a mini silicon effect in Seattle. The growth of Seattle had nothing to do with the prices in San Francisco. I think prices have very little bearing on this kind of things.