Cost of living is always important to consider. Looking at this site[0] for a ballpark figure, it would seem that someone living in San Francisco needs to be earning at least the double of someone in Berlin, to afford the same standard of living. San Francisco is still a very attractive place to work as a Software Engineer, but it's not as black and white, as the huge difference in pay might make it look.
Software engineers most of the time get fed by the company and i distrust, at least with my spending habits, the cost of consumer prices like clothing or gadgets being cheaper in europe than in the us.
Housing is the main difference: you can get a fairly large place in berlin, and you can have a family there. But SF is one city, there are pleny of other cities in the us more family friendly (if not any other city).
I remember recently a map showing the purchasing power by salary per state, and the biggest purchasing power was nebraska.
[0] https://www.numbeo.com/cost-of-living/compare_cities.jsp?cou...