America offered more than a place to explore. France, Germany, and England lost thousands of civilians to terrorism by religious zealots. On top of that, overpopulation in some areas, degradation of farmland in others, and deep economic divisions between rich and poor caused misery, disease, and mass starvation. Europe needed an escape hatch.
Non-Americans earn 57% of engineering doctoral degrees, 53% of computer and information sciences doctoral degrees, 50% of mathematics and statistics doctoral degrees, 49% of engineering-tech and engineering-related doctoral degrees, and 40% of doctorates in physical sciences and science technologies.