But Germany has great public transport, excellent beers, free/close to free healthcare and liberal icon like Angela Merkel. That is all good hackers/developers care about.
That is all true, but the thing is that most of the developers I know are single and have lots of time on their hands. Some of them literally play computer games only in their spare time. I decided I want to have kids and so I have a family now, and I can tell you having even just 1 kid is expensive enough. Me and my wife we both work full time, only to have enough spare money at the end of the month to put aside, just so we can believe this money will be worth something in 30 years or so (I don't believe it). And we are not living an extraordinary/luxury life. I'm not materialistic, and I only care about money because I need it to keep me and my family alive. Germany is quite expensive in that regard compared to the average salary.