Silicon valley started because there was masses of land in California's orange groves almost for free.
Then WWII lead to a huge demand for electronics and components for the local aerospace industry. This attracted lots of engineers, as did the local world class tech universities.
Bill Hewlett and Dave Packard went there to get jobs and started HP in their garage which grew into a $Bn company which later employed Steve Wozniak who started his own company in his garage which grew into a $Bn company ....
While we have some overpriced office space in a couple of warehouses in a fashionable bit of Central London where a few media types sell imagineering services to each other.
It would make you laugh if you weren't crying.