Don't take the Olympics as a measuring stick of the US's amateur boxers.
Rau'Shee Warren

http://ca.youtube.com/watch?v=_XMJxeB_x_s
this is against Carlos Ortiz of Peurto Rico

http://ca.youtube.com/watch?v=vFU7IsZWoqs
after he beat the best fighters of the 54kg this is his final fight

Demetrius Andrade in 2007 world championships, there is a reason he was #1 ranked WW in the amateurs.
http://ca.youtube.com/watch?v=zdxePkaT-4E

Gary Russell Jr
http://ca.youtube.com/watch?v=w6njoG_31N0

Gary Russell III vs Emanuel Taylor
http://ca.youtube.com/watch?v=a1SNU8JvkYw 06
http://ca.youtube.com/watch?v=_2kEma...eature=related 08

These are just a few of the guys, but there are plenty of amazing talent in the amateur ranks.