Because we don't want to live in US. Because we dont like US culture. Because there's more to quality if living than just raw dollars.

This is asked in like every thread about Europe. Read about income tax and the social services states provide in the EU. I'm happily giving up that "80%" for those.

Because European talent is largely confined to EU so gotta take what's being offered.

Because the talent can't get into America because of its terrible immigration system.