Except all those teams lacked experience when they were first won
Giants, for the most part, yes, but a number of the Cards had been in the 2004 and 2006 world series when they won in 2011 (Carpenter, I think Wainright, Pujols, Molina I think, probably more).
Edit - BTW - I'm only referring to the teams that won recently. As for the 1996 NYY, they had almost all gone to the playoffs in 1995, other than Jeter. Joe G was the main catcher, Tino went with the Mariners, Rivera I think was a rookie but a set up guy. . .