Because the Miami heat and the San Antonio Spurs were such great teams back in the 80's and 90's?
From Wikipedia:
http://en.m.wikipedia.org/wiki/List_of_NBA_franchise_post-se...
"Of the 30 current NBA franchises, 13 have never won the NBA championship. The oldest such franchise is the Suns (46 seasons), while the Royals/Kings and the Hawks have even longer championship droughts (63 and 56 seasons, respectively). Only 7 franchises have never been to the NBA Finals, the oldest of which is the Braves/Clippers (44 seasons), and again the Kings and the Hawks have appearance droughts that are even longer (63 and 56 seasons, respectively). The longest a franchise has gone without appearing in the playoffs at all is 15 seasons: the Braves/Clippers franchise from 1977 to 1991."
Only 7 teams have not been to the finals. That's not awful.