Since the US didn’t start sending pros until 1992 it wouldn’t be fair to include players who weren’t eligible. So for the sake of argument let’s say they had to be 30 years old or younger at 1992. So players like Kareem/Wilt/Bill Russell/Jerry West/Elgin Baylor/Bill Walton aren’t applicable.
With those parameters who is the best American player without a gold medal?
It has to be Tim Duncan if we’re only considering post-1992 players. Duncan could have played in 2008 or 2012 if he wanted, so he’s kind of in the same boat as Kareem and (more or less) Walton.
Kareem and Walton both famously declined to participate in the Olympics when they were each the best eligible American, so I’m not sure excluding them makes sense. Walton’s year didn’t win gold, so his refusal may have decided the outcome. The balls on Kareem, man.
Bill Russell and Jerry West did win gold, also.
Why didn’t Walton play?
He never explicitly said, but either/or to protest the Vietnam War, and because he absolutely hated playing on the 1970 World Championships team because the coach was a grade a douchenozzle.
Walton’s refusal didn’t cost the US anything. The Soviets won because of corrupt officiating. If Walton had been there, it would have played out differently but the officials would still have ensured a Soviet win
USA would have won if Walton played. He was one of the best players in the world and even with all the corruption the Soviets only won on a miracle of a play.