Earlier quoted context omitted.
You are completely ignoring the fact that the cost of living is much higher in Zurich than the rest of Europe. (For example, the rent is around 10 times higher than in Prague). But after-all, you are a recruiter, why would anyone expect you to provide unbiased information, right?
Zurich is not comparable to London, Berlin or Prag due to the fact that it is an order of magnitude smaller than most European cities. The diameter of Zurich is just 13 km. The city itself is tiny and the "city center" is even tinier. This leads to the variance of the rent being very high: In the very center of town you might have to pay 1500 CHF for a 1-bedroom apartment, but if you can live also 5 km from the city…
That's cheap compared to London (zone 1).