Earlier quoted context omitted.
Consider Japan: (fact) a single market with a single language (fact) geographically isolated (fact) not much space (fact) burned to the ground in WW2 and yet for a while it was an economic powerhouse on the world stage. Taiwan, Hong Kong and S Korea, similar stories. So what is the common thread? Free markets.
Japan is a relatively populous single market with a single language -- about 125 million people at present. It's smaller than the USA, at about 332 million; but almost 60% larger than the most populous Western European country, Germany.
Germany is home to approximately 83 million people. Japan 126 million. Japan is 40% bigger than Germany, not 60%.
US is roughly 334 million. Europe is rougly 748 million, of which the EU is roughly 447 million.