Lack of arenas in Europe deters NBA
Stern still believes it will happen. I really don't know why he's still trying. International teams have no place in a national league. There's the question of travel and the possibility of players being traded across oceans...I don't think a World Basketball League would work out as well as Stern might hope.
A few more international tournaments featuring each league's champions (like the McDonalds' Open) would be nice, but I think each country should have its own professional league. The nature of the NBA - the rookie draft, trades and so forth - doesn't seem suited to a league that would span the globe.