£35,000 salary in the UK has the same buying power (for want of a better expression as a $60,000 US salary. Adjust for "because London" and you're looking at £45/55K (not hard in London) equating to $75K - $100K.
Thinking about it, I know a dozen or so people in the "poor deprived" north east of England earning over £40K who are under 30 years old so we're not all badly paid.
Well 45/55k is /cheap/ for a senior dev. Unless you work for a bank/inner london (or google) all you can hope for is perhaps 65k, at the top...
So yeah, if you want more, the only way is to sell off and 'manage', or go off contracting.
There's many junior 'managers' who can barely lace their own shoes who get quite a bit more than 65k.
The difference is that Brits feel poor when they come to the US, whereas Americans feel rich when they come to the UK.
Sure, PPP (Purchasing Power Parity) comparisions are important (e.g. it's easier to live in Thailand with $1000 per months than in NYC), but absolute values matter as well.
That's probably the 20% VAT that's included in the price. If you are coming from a state with no sales tax, this could explain your surprise. Hell, coming from Canada where I was paying 13% sales tax (never included in the sticker price), I found UK prices shocking.
I live in one of the most "miserabilist" parts of the UK (where Morrissey grew up, just to mention one celeb), and everyone goes crazy for Disneyland. We don't have direct flights to SF but we get dailies to Vegas and Florida. 'nuff said.
Sure they matter, but only to the extent that foreign expenditures are a part of your costs.
I.e. sure when you go to the US and have to buy USD with GBP you'l be at a disadvantage, or when you buy some electronics priced in USD, but how big a portion of your spending is that compared to food/rent/commuting/hobbies etc., all of which are priced in your local currency.
Wrong way round, when I go to the US I generally don't bother looking at the price of things as it's all so cheap. Even if the exchange rate was 1:1 it would be cheap (decent clothes are amazingly cheap, petrol/diesel is laughably cheap and eating out is great) but with the exchange rate being the way it is it's even better. The was a time before the crash when the exchange rate was $2 to the £, so long as you could afford the flights over you could have the best holidays in the US.
This is only true when being a tourist though as you are thinking in your native currency and basing purchasing decisions in that frame of reference, when you actually live and work in the respective country then (ie if you move to another country) then that stops being an issue as you are earning in the new currency.
Thinking about it, I know a dozen or so people in the "poor deprived" north east of England earning over £40K who are under 30 years old so we're not all badly paid.