The world has certainly closed the gap on the US since '92. I think that's apparent.
However, there was also a stretch there where the USA wasn't exactly trotting out there best there. 2002 being the most obvious example but the same can be said for the team that got beat in Athens. 2004 and you have no KG, Kobe, or Shaq. '06, you had a decent team in FIBA but again, no KG, Duncan, Kobe, or Shaq.
The USA wasn't exactly trotting out their A squads for a few championship cycles there. When they're loaded (2008 & 2012) with the best of the best, it's a bit of a different narrative.