^And were all in their own way
The US has had even worse luck with Jr World Ice dance medalists, especially gold medalists:ONLY 3 American men have medalled at both Jr. Worlds and the Olympics
After a 14 year Dance medal drought at Junior Worlds, the US won Jr Worlds dance gold in 1998. From then until now the US has had 6 Jr Worlds gold medal teams, only one of which (Belbin/Agosto) went on to win an Olympic medal.
1998 Gold - Joseph/Butler - went to Nagano in 98 (21st) split up that summer.
1999 Gold - Silverstein/Pekarek - 12th in 2000 Worlds then split the next year. She did make it to the 2006 Olympics with another partner (16th)
2000 Silver - Nussear/Forsyth - split after that season. Neither reached Senior World or Olympics with new partners.
2000 Bronze, 2001 Silver, 2002 Gold - Belbin Agonsto - Olympic Silver in 2006 & World medals
2004 Bronze, 2005 Gold - Matthews/Zavozin - 16th at Worlds in 2006, split the next season. He did make it to the 2010 Olympics with a new partner, skating for Hungary.
2006 Bronze - Davis/White - Olympic Silver in 2010, World Champions in 2011
2008 Gold - Samuelson/Bates - skated in 2010 Olympics (11th) - didn't compete together after that season. Now competing with Chock.
2009 Gold - Chock/Zuerline - split in 2011
I stopped after the most recent Olympics because we don't know yet how the others will do. Still, you get the idea that, for US teams at least, Junior Worlds success isn't a very good predictor of future success.