I've noticed that before. During that long quarter-century champioship drought between the '83 Sixers and the '08 Phillies, Philadelphia teams that played for championships routinely ran into the brick wall of dynasties, including in some cases emerging dynasties (1980 Islanders, 1997 Red Wings). It's hard to call the Astros a dynasty, except maybe an AL dynasty. All they have is one WC and that was five years ago. Also, the 2009 Yankee team was a standalone champion and that was their first WC since 2000 and first WS appearance since 2003 and they haven't been back to the WS since. The 2010's was the first decade in a century in which the Yankees did not appear in a WS.
The '83 Sixers was the only NBA team not named the Lakers or Celtics to win an NBA Championship from 1980-88,