Britain thought that General Kitchener's use of the Maxim machine gun to slaughter the Sudanese put them on top, as well. That and a host of other innovations, such as in shipbuilding, were still not enough to preserve its empire.
One item that the article I posted doesn't mention is the worldwide transparency of scientific discovery. Almost none of that U.S.-financed military research is under absolute wraps, without discussion of basic science supporting it and much of the technology that results. (The last such notably successful example of secrecy, I'd say, was the A-bomb's Manhattan Project.)
What the controversy over Clinton's disgraceful leaking of U.S.-taxpayer-funded research to the Chinese ignored was that this accelerated what would have happened eventually. That certainly doesn't excuse it -- but the U.S. government wouldn't be the first world power to underestimate the power of the diffusion of research through the worldwide scientific community. Britain certainly did.