>That aligns with the state of the art having a home in Europe around then.

Does it? Bigger doesn't mean more state of the art. Comcast isn't state of the art. Exxon isn't state of the art. Most big companies aren't Apple.

Moreover, the size of American companies is somewhat exaggerated cos of liquidity being pumped into the stock market.

The US gov didn't pump liquidity directly into the stock market: they reduced the cost of borrowing, which increased investment in basically everything, e.g., collectible baseball cards. My point is that investors bid up the price of European stocks as well as US stocks.

Who says the change was in Europe? The US got around to leveraging its comparative advantages in internet tech and grew some huge companies. The Facebook was never going to emerge from Poland, no matter how much public policy tried to support smart Polish engineers building PHP frameworks for people to upload pictures of their friends. Europe did not create any Facebooks, but achieved comparable productivity and GDP growth rates spread across a more diverse range of fields, and excelled in fields like Coronavirus vaccine research despite comparatively modest success stories in selling digital advertising. It is not obvious that we are worse off as a result, or that a giant company like Facebook is substantially more likely to come up with the Next Big Thing in technological progress than a merely large one like Siemens, or even a reasonably well capitalised research company well outside the top 1000 firms. The value of growth is demonstrated in goods and services, jobs and potential for goods and jobs across the entire economy, not in vanity metrics like number of companies with enough monopoly power to show up in top companies indices.

(And China was always going to move up the value chain in consumer electronics and grow faster than both of us; when it does so further in the next couple of decades it need not represent a flaw in US/European policy)