Obviously the famous "I know my place" sketch works as well in Sweden as it does in the UK.
Salaries are often set relative to cost of living. e.g. I get paid more as an engineer in London than I do in my hometown but the difference is almost equal to the difference in cost of living. Therefore comparing an SV salary to 'Europe' isn't easy as there are very rich European cities as well as very poor ones. SV and in particular SF has an incredibly high cost of living compared with pretty much anywhere in Europe so it's not easy to compare SF salaries to even those in more expensive European cities like London.
Ok London has better transport links than SF but that isn't cheap either.
Overall I guess the salary difference isn't completely justified by cost of living differences however in London working hours seem to be kept in most places (9am-6pm) and we get more holidays (typically 20 days + bank holidays - about 8 per year -) whereas people in the valley seem to get fewer holidays and work longer hours. Maybe that perception is wrong but if correct maybe that is what justifies the higher salary.
Camden is well over $4k PCM in Belgravia its over 6k
That's like comparing costs in Bedford 65 miles away from London fast train take's 35 mins to St Pancras - Slow train is less than an hour to the city.
I said Zone 2, 20 mins out.
I guess it's really impossible to compare. London's a much bigger city with so much in the centre (tourist stuff in particular) that I don't think it would actually be very nice to live there. Whereas if I lived in SF I would like to live quite central.
I'm guessing the underlying causes are the same.
But I suspect the dominating cause for the wage difference is simply that European wages across most industries generally are just lower than American wages.
[1] http://en.wikipedia.org/wiki/Category:Computer_scientists_by...