Right from the first paragraph I know this is just nonsense that is only being posted because of currentpoliticalthing
The US leapfroged the rest of the world in both science and engineering by it's civil war, this isn't disputable. It could only do that because of decade long tariffs that existed solely to protect it's nascent manufacturing industry.
People have constructed so many myths about WW2 it's crazy.
GDP: 1871 the US passes GB By 1900 the US economy was double GB's size. by 1910 they've already passed them by GDP per capita. INDUSTRIAL OUTPUT: Again 1870s. You can't really untie science from industrial output. Is there argument here that the US was behind scientifically because of Nobel prizes? If you narrowly define science as "things europeans liked to research" then I guess. But even by that definition Americans were discovering new drugs such as Actinomycin D as early as 1940, during, not after, WW2 and before they entered. So unless people like Waksman (educated in America) count as braindrain 30 years before the fact I don't think the argument is credible.
The UK failed to mass produce penicillin. It's this industrial ineptitude that caused "brain drain".
Was it tarrifs or just a large, highly educated population with a unified market? The US has always been one of the leaders in education and scientific research on a per capita basis. Even in the 1770s you har people like Franklin working on cutting edge physics (the standard sign convention for charge is still flipped because of him). At some point it also just outgrew all the other countries in terms of size and it naturally became the global leader around that time.