It's not difficult, at present, to see the world of difference between the NBA's two stilted conferences. There are two teams in the East with records better than .500 to 10 such teams in the West. There are four below .500 teams slotted for Eastern Conference playoff spots at the moment -- including one as the 4th seed -- when such a record would rank 10th or so in the Western Conference field. There are deep ranks of quality on one side of the aisle and an ultra-stratified hierarchy on the other, where the Pacers and Heat rule over a 15-team pool with a complete dearth of a middle class.
Blame mismanagement, bad luck, questionable development, ownership pressures, or the dominance of the Heat as discouragement. Whichever the road (or combination thereof), it has led to a disparity between conferences that -- if it continues apace -- would be downright historic. According to data drudged up by Neil Paine of Sports-Reference, the West's dominance over the East in win percentage is slated to be the greatest single-season disparity between conferences since 1960. In that season, Eastern Conference teams won 60 percent of their overall games and 70.8 percent of their games against Western Conference foes. Through almost a quarter of the 2013-14 season, the West has posted a slighter win percentage (56.7) overall, but has managed equivalent cross-conference dominance by claiming 70.8 percent of the matchups against Eastern Conference teams.
So continues a much longer trend of Western Conference supremacy. Since the turn of the millennium, only once -- the 2008-09 season -- has the East claimed the better win percentage between the two conferences. That campaign most memorably saw three Eastern contenders (Cleveland, Boston, and Orlando) finish out the year with 59 wins or more, but it was an exemplary -- and aberrational -- showing from the entire conference that sealed the deal. Somehow, 14 of the East's 15 teams finished that season with 32 wins or more. The lack of a true basement helped to lift the Eastern Conference just over .500 overall, with the West finishing out the year at .495. The league has otherwise been controlled by the West through the 2000s, though never to the degree we're seeing now.