The more important US vs Europe difference is that in US there's much more funds for the research -> startup -> scaleup stages.

There's plenty of academics doing fundamental research in Europe. But somehow the ball is dropped on turning that research into successful businesses. So eg. uni graduates doing research in EU, then move to US & found a startup there, is sadly a common pattern.

As I understand it, mostly due to funding suppliers (gov, VCs, banks etc) being more risk-averse than in US. Regulation pressure doesn't help either.