The idea that the NBA needs to implement revenue sharing in order to help small market teams and thereby maintain, restore, or create competitive balance is, I think, obviously absurd. The NBA really is one of the least-balanced major sports leagues around. But small market disadvantages have nothing to do with it. Neither the post-Ewing Knicks, the post-Jordan Bulls, nor post-Shaq Lakers have been able to leverage large markets into NBA success. The Spurs in tiny San Antonio (37 on the Nielson media markets list) are the most consistently successful team of recent years. Detroit is a modest-sized market at 11, as are the current champs in Miami at 17.
I think the main thing about competitiveness in the NBA is that as these dudes note there are very, very few people in the world with the appropriate physique to be NBA-quality big men. As a result the variance in big man quality is gigantic and this is semi-intrinsic to the sport. At the same time, the max salary rule ensures that the very best players in the league are underpaid, as are the very youngest stars. So there’s a lot of essentially luck-based imbalance (i.e., Dwayne Wade is worth max money, but LeBron is worth even more money, but they both make the same, so Cleveland gets a better player but has the same cap room to find a supporting cast) playing out. Then, the combination of guaranteed contracts and the salary cap means that it’s hard to undue the consequences of management fuckups so that even a great hoops genius probably couldn’t turn, say, the Knicks around.