In my opinion there is less opportunities there (In Switzerland) higher starting salary, then people get stuck in the middle 120-140, and can't shift past. (for the reasons mentioned below). Because managers don't want to pay developers more than themselves.
HOWEVER, that same problem exists in London, but is typically solved by developers going day-rate contract. That way management can justify and still get experience.
Because the market is smaller in Switzerland it does not make it so easy for a day-rate contractor market to exist..
So, my point is, if Switzerland is better than London for developers on a global level. Its only marginal. But compared to other salaries, Doctors, Dentists Lawyers, Engineers etc. Developers in London are well paid (treated as technical roles similar to those mentioned) Whereas in Switzerland developers are paid half++ of those jobs.