IQ levels do vary considerably both between countries, and also between different groups of countries. See for example the website www.brainscan.com
This survey and other similar ones consistently identify the highest IQ levels as being - not in the "white" countries, but in East Asia. Typically, country-by-country IQ surveys place Singapore, South Korea and Japan as amongst the top four or five.
European civilisation was not always the world leader. That has only come about in the last 500 or so years. Prior to then, Asia was very much in front - and by the way things are going, could well be poised to once more steal the show!