I think the difference is much more along the lines that the US is a big enough market (without language barriers) that it is possible for US developers to writ

I think the difference is much more along the lines that the US is a big enough market (without language barriers) that it is possible for US developers to write much more types of software than you can feasibly write and sell in the EU. Same for Asia outside of China and Australia. EU people can write software. They don't because it's not worth it. And of course, this happens in large numbers. The bigger the market, the bigger the software industry. But even Germany isn't even a third of the US market for software. The actual people aren't different. You just can't achieve in the EU what is possible in the US, and I don't mean "become a millionnaire", I mean "provide for yourself and maybe a family". Especially since the US has places to live that are far cheaper than the cheapest place to live in many EU countries like the Netherlands, or the kind-of-EU Switzerland.