The NBA has required the Cities which house their teams to maintain a suitable arena. Based upon that condition the NBA will keep a team in their current location. If that condition is not met then the NBA's position is that a City cannot keep the team and a more suitable location must be found.
I think it is important to note that Seattle was an example of this and served as a lesson to other Cities. They could not get a new arena built, they no longer met the requirement for having a team, and lost the Sonics. Right or wrong, who is to blame or not blame, that is what apparently happened and the NBA moved them to OKC. This served as a harsh lesson for other Cities. Build a new arena or else...
This condition has, however, been met by Sacramento. Sacramento has a new arena plan and financing in place. Stern and other owners consider it a good deal. Good enough to loan the Maloofs the money they need to get it done. But the Maloofs refused and still want to move the team.
This violates the NBA's own conditions. That the City maintain a suitable arena and if that is done the team stays... Sacramento has done that, demonstrated they learned the Sonics lesson, and because of that should keep the team. The NBA doesn't require that the Cities maintain a viable ownership group. They will step in and find that if needed, e.g. New Orleans, to keep the team in their current location.
Further, moving the team away from a deal for a new arena would really create a lot of confusion. What does a City have to do to keep a team if building a new arena isn't enough? To take the our team away from Sacramento after all the City and fans have done would be to create an even worse wound in the fabric of the NBA in an attempt to heal the Seattle past. Just when Stern has taught Cities the build or lose your team lesson it goes out the window?
Sacramento has learned the lesson the NBA has put forth through the loss of the Sonics and met the conditions for keeping the team. We have gone above and beyond the call. KJ raised 10 million in corporate sponsorships. Fans sold out games to make a statement of support for the team. What more can we do?
To move the team after all that has happened would be truly awful. Future cities would definitely be more skeptical of making the same kind effort. They could just lose their team anyway. Why go to all the trouble?
The answer really is that the bar for getting a team back would be even higher. Unlike the one main condition for keeping a team, there is a whole host of other conditions that would have to be met to get an NBA team back.
You would have to demonstrate that you are a viable market that doesn't infringe on another team, have an ownership group in place that has adequate capital, demonstrate that you would be a good professional team owner, and have a suitable arena. Even then all that might not be enough. There aren't enough NBA teams to go around and it isn't easy to get a team. You would have to compete with other Cities that could also meet these standards.
Seattle is stepping up and prepared to build a new arena. There is an ownership group in place in a market that doesn't infringe on another NBA team, unlike Anaheim. They would seem to meet the conditions for having a team because they are a proven market and have a proven brand they can re-establish in the Sonics. But even that might not be enough. Sadly, there is no guarantee they will ever get another team.
The main reason I doubt they get the Kings is that when a community shows the support that Sacramento has done it would be hard to move a team. The NBA has trumpeted having a new arena as the condition for keeping the Kings here for so long that to move them when a plan is in place sets the NBA back quite a bit. The NBA would lose a huge amount of credibility by moving them after the whole City and its leadership has stepped up and met the demand for a new arena.
Also, it would just be plain ass idiotic. To create another Sonicgate to heal the past one is just dumb. The only true way to resolve and begin healing the wounds of losing the Sonics is to give them an expansion team and keep the Kings in Sacramento. Otherwise, the new Sonics franchise will be forever tainted. Sullied by Sacramento's loss.
And, probably more important, what would be a clear victory for the NBA in requiring and getting Seattle to build a new arena would be overshadowed and confused by the Sacramento loss.
If the NBA wants to maintain their condition, requiring Cities to build arenas, to keep a team they can't just walk away from Sacramento now. That message and the lesson they would have taught other Cities by Seattle losing of the Sonics would be lost.
That message is, however, completely reinforced and affirmed by awarding Seattle an expansion team. The NBA and Stern got what they wanted and by doing so further put other Cities on notice. By doing so they further validate the condition that Cities must continue to meet in order to keep their teams.