I think this happened not because USA lost a lot, but because others gained ground. USA, despite all it's losses, was much better than most after WW2, industrial gap was enormous. Now other countries caught up in easier areas and the gap is smaller. Very obvious examples - Russia (USSR). They were stagnating in tech sector up to nineties end, then oil money bridged part of the gap and now Russia is immediately arrogant, "going it's own way" and all that rhetorics.