I also observe that Europe has several (more than the US) Fortune 500 companies that had no problem crossing the cultural borders, so again. Its not just a matter of cultural barriers.
And if you think Northern Europe and Southern Europe is different then you are right, but so is New York and SV and LA and Mississippi and Texas.
So yes it can explain some of it but not all. Unicorns do happen in Europe and Rocket Internet have been fairly good at expanding their business even to non european countries.
And last but not least. Yes you can compare the EU and the US in fact the tradeagrement is between those two parties and the EU is constantly working to harmonize the markets.
So I don’t believe it’s as easy as I know many Europeans feel like.
But sure culture does play a part.