The significance of Silicon Valley is overstated. East coast had Commodore, Rockwell, Carnegie Mellon. The west coast had some neat stuff, true, but near every thing of size happened more and earlier east coast.
You mean like Microsoft, Oracle, Intel, Apple, etc? Oh wait, those are all west coast companies and still going strong. East coast has all the failed computing companies (DEC) and the ones that only survive because of a massive influx of tax payer money (IBM). Other failures that I'm unsure as to location would be Novell, Compaq and HP. HP still makes excellent printers and support devices, but their computers were junk. Novell is west coast, I think, and still in business, but no where near where they were or maybe could have been.
How can you not consider Commodore a failure, are they not out of business yet? I think Xerox is east coast, but since they weren't capable of hanging onto to their patients, nor getting the vast majority of their inventions and break- throughs to market before their competitors were able to, the are an abject failure considering where they should be today.