Biggest loss has been the distance from family, especially during the pandemic (though of course I couldn't predict that). You don't realize how far away you are from someone until you hang up the phone with them and feel the distance set in.
Moving to Germany from a European country is as simple as crossing the border. Moving to the US for most people in the world is a nightmare.
I for one would never go back to the US now that I live in Germany. The few British people I know moved to Germany before brexit kicks in to literally escape from the UK.
Money isn't everything, not many people change their entire life and move to other countries for money alone
Europe (at least the technocratic level) has been pro immigration for a while, so network effects probably also enter the equation.