It will never happen. Vegas would never agree to taking every game OTB. They are willing to take the All-Star Game OTB just to get it in town, but that is because the books all know the town will be swimming in money if the game came and so they wouldn't care about lost betting opportunities because the pits will make up the money tenfold. I don't see them ever going beyond that, nor would I expect it.
NCAA betting on games here makes sense. They legalized it because everyone said Nevada was being hypocrites for not having Nevada games OTB. After legalizing it the action on the games hardly went up, no book ever says "wow I am swimming in Rebel or Wolfpack money". Its been such a non-event to have the games up. Same would happen for the NBA. People going to fights bet a lot of money on what they will be spectators for, but the other sports just don't draw that sort of action. Arena football betting on the Gladiators is only slightly higher in action for home games than road games and hardly any higher than handle on other arena games. If the NBA or anyone else wanted to do a real study without bias they would figure out what a pathetic joke it is that they worry about these things. They almost bring it on themselves by always mentioning it, making fans outside the state think about it too much. If they just ignored it and left everyone to act professionally, like they do in pretty much the rest of the world, it wouldn't be a consideration at all.