> Because you don't risk bankruptcy by having a health issue, if you're single it's not a sausage fest, more laid back work (in SF it seems you're bound to stay longer times at the office), greater tourism choices (a short trip away) and probably still cheaper than rent in SF even if we're talking London

We have another reason right in this very answer: People in SV are willing to take more risk and sacrifice. Sure there are chances one may be bankrupted because of a health issue. Sure there are fewer entertainment choices. Living in SV may not be an ideal lifestyle for many but it has attracted a lot of adventurous mind from all over the world, who together conjure up trailblazing ventures.

Not only do I not think that is true, I think there's real danger that people conclude that more risk is better. SV is in many ways risk averse. The days when any kid could get a million dollars are over. Almost every success story seems to happen on a background of brand name colleges, companies, incubators or investors. What I think people mean when they talk about risk is really "hype". People move to SV to work in the tech industry because that is THE place to be. You don't have that in London, Berlin or even New York. The pure momentum of the industry simply overshadows any health care, housing, dating problems in the bay area.

> Not only do I not think that is true, I think there's real danger that people conclude that more risk is better

I don't think people in general consider more risk being better. Rather, higher reward often comes with higher risk. People aim for higher reward obviously have to accept the risk associated with it. It just so happens that, as you said, SV is the place to be for the tech industry.

> SV is in many ways risk averse. The days when any kid could get a million dollars are over. Almost every success story seems to happen on a background of brand name colleges, companies, incubators or investors.

I don't argue for or against the risk averse nature of SV. And of course, knowing the right people helps get your foot in the door everywhere. Undeniably though, for variety of reasons, there exists an ecosystem in SV that breeds the creation of hi tech businesses. If you want to make a name for yourself, being in SV makes a lot of sense. It isn't easy to replicate that elsewhere.

Just look at the list of car companies that set up shop in SV in the last few years:

https://media.ford.com/content/fordmedia/fna/us/en/news/2015...

http://www.technologytell.com/in-car-tech/1848/volvo-geely-g...

http://www.technologytell.com/in-car-tech/1798/renault-nissa...

http://www.industryweek.com/expansion-management/expansion-m...

VW has been there essentially forever, apparently: https://en.wikipedia.org/wiki/VW_Electronics_Research_Labora...

Those are big names in a very established industry, yet they can't afford not to have a presence in SV.

Why would you risk bankruptcy? Every company in Valley typically offers great health insurance. London rents are more expensive than San Fran in particular areas and buying property has become nearly impossible at any reasonable price.

Gender distribution is not particularly different in the European tech scene than in the US one. Quite a lot of companies (both in the startup and agency world) have no female employees.

Hours I'd assume wouldn't be so different in a real startup, since that sort of business kind of depends upon its employees not really doing anything else in the day.

And rent is definitely not cheaper, not if you want to live anywhere decent.

Still, you're right in terms of tourism choices, and it's a lot easier and more enjoyable to explore London on foot.