Yeah, but the The City is a tiny pebble in comparison to London. I'm sure there are plenty of places in London that size that are dominated by one industry (though none with their own laws.)
How is this different to SF (the 'city' in London isn't actually that big and smaller if you mean 'the square mile'), I assume most people commute to SF in as well?
It's not an apt comparison as firms are geographically distributed all over the bay area.
But people still commute there right? This is the point i'm trying to make, No one (and by that I man a small minority) lives in the city centre because it is too expensive. Applies to any major city on Earth which has suburbs.
I imagine the population during the day swells more than 100 fold...
The City of London is a weird ancient administrative division. It's not the whole of the city centre by any means, and not at all comparable to San Francisco.