The Mavs have basically no upcoming draft picks and have tons of money committed to old and aging stars and have a terrible coach, GM, and owner. The NBA has doomed the first great white American player to enter the league in several decades to spending his first 8 years on a bad team. They also have set up the Spurs (a team with a small fanbase) to win several championships. This was the worst rigging imaginable from the NBA's perspective. A good rigging probably sends Flagg to the Wizards to establish Washington DC as a big basketball city and the Wizards have interesting young players and assets to build around Flagg with.
Did the NBA rig the 2022 draft as well by having 2 of the 5 smallest franchises in the NBA (Orlando and OKC) the top two picks in a two player draft too.
Texas is a huge market & has experienced a major growth in recent years due to the exodus from California. DAL & SA both have history & well established fan bases while WAS doesn't.
Dallas already has a history of embracing foreign white players. Now they get an American white player to embrace as a reward for keeping LA relevant. Why would the league want to damage a Dallas market that just went to the finals? Also, AD & Kyrie (when healthy) isn't a bad supporting cast in the short term. I wouldn't be surprised if they struggle for a year/AD gets injured & end up with another high pick to help them build for the future. It would also be somewhat fitting for him to flounder for the first half of his career in Dallas & then win a title or 2 towards the end similar to Dirk. Lebron also took a similar path with CLE.
As for the Spurs, they already have a history of winning titles with dominant big men so it made perfect sense to send the next generational big to San Antonio. It also made perfect sense to hand them yet another high level asset in order to assist them in furthering that history. I expect it to be traded for an established star but either way, the Spurs are even better set up for the future. Which is clearly in the NBA's best interest as Wemby is obviously the future face of the league.
LA, BOS, NYK, CHI, etc will always be somewhat relevant (at least financially/ratings/attendance wise) due to their location & history so it makes sense to place superstars in other big but less established markets in order to further the reach of the league. Just look at CLE for example. I believe they were 7th in home attendance this year. Before Lebron, they were a completely irrelevant franchise.
It also made sense to make the collateral move of Luka to Flagg for Dallas & the NBA as it now puts the next white superstar in the biggest established market that will most embrace him while putting the biggest current international superstar on the league's most internationally known team.
When billions of dollars are on the line, whoever stands to benefit or loss the most will always do everything they can to get the result that is in their best interest. Why would the NBA be any different? Especially when there's no real regulatory system to stop them?