• Miriam Adelson and her family are buying a majority stake in the NBA's Dallas Mavericks from Mark Cuban.
• Adelson and her casino company, Las Vegas Sands, have spent millions in Texas to push for broader legalization of gambling.
• Cuban, a proponent of legalized gambling, said last year he was interested in partnering with Sands.

News that Miriam Adelson and her family would sell $2 billion in Las Vegas Sands stock to buy a majority stake in the NBA's Dallas Mavericks stunned the sports and gambling worlds alike.

After all, Las Vegas is the headquarters of the family's empire, even if it doesn't have any casino resorts in the city anymore. Adelson is the widow of Las Vegas Sands founder Sheldon Adelson, who died in January 2021.

And Las Vegas is now a preeminent destination for sports, with the NHL's Golden Knights, the NFL's Raiders, the WNBA's Aces and a Formula 1 Grand Prix. Soon, Major League Baseball's As are expected to relocate to the desert from Oakland.

Likewise, NBA Commissioner Adam Silver has suggested it's a matter of when, not if, Vegas gets a team. LeBron James has said he's interested in bringing basketball to Vegas at some point. Retired NBA legend and former Sacramento Kings minority owner Shaquille O'Neal has also expressed interest in a Vegas team. The city is also set to host the final games of the NBA's midseason tournament.

An NBA team in Vegas could command a price tag in the $6 billion to $7 billion range, according to Patrick Rishe, director of the sports business program at Washington University in St. Louis.

So why is Adelson and her family throwing billions into a Dallas team?

In a statement to CNBC, they said: "The Adelson and Dumont families are honored to have the opportunity to be stewards of this great franchise. Through our commitment and additional investment in the team, we look forward to partnering with Mark Cuban to build on the team's success and legacy in Dallas and beyond."

Patrick Dumont is married to Miriam Adelson's daughter, Sivan. He is also the president and chief operating officer of Las Vegas Sands.

The Adelsons have already invested millions into political contributions and lobbying in Texas, trying to coax lawmakers into more broadly legalizing gambling in the state. Las Vegas Sands itself has spent years and millions of dollars as well in pursuit of the same goal.

The company sold the Venetian, Palazzo and the Venetian Expo center in early 2022 to affiliates of Apollo Global Management and VICI Properties, raising more than $6 billion. The company has said it intends to use that capital to pursue gaming licenses elsewhere.

Late last year, Mavericks owner Cuban said he was interested in partnering with Sands to build a development that would include a new arena and a casino resort if the state more broadly legalized gambling.

It didn't, and the campaign is still in limbo. State lawmakers failed to push forward legislation that would bring it to Texas voters as an option on the ballot. It's unlikely they'll take another stab at it until the legislative session in 2025.

"When you think of all the places you want to save up to vacation, Texas isn't one of them," Cuban said earlier this month, according to The Dallas Morning News. "There's no real destination that you save up for. That's a problem and I think resort gaming would have a huge impact."

Owning a team in Dallas will strengthen the Adelsons' ties to Texas. Possibly, they would gain both a carrot and a stick to get local support for a casino license by wielding power and influence over the future of the Mavericks. A company insider told CNBC that it's just smart to strengthen community ties.

It's a similar strategy that Las Vegas Sands has deployed to secure one of three new casino licenses to be awarded in New York.

The company has invested millions of dollars and many years of lobbying efforts to woo government and community leaders in Long Island's Nassau County. And the company has committed to redeveloping the Nassau Coliseum into a destination mixed-use resort, regardless of whether it wins a license. But the size of its investment presumably would depend on whether it can offer casino gambling.

Adelson stands to benefit mightily if the bets on eventual casino licenses in New York and Texas pay off. She and her family will continue to own more than 50% of Las Vegas Sands stock.

There's still a great chance the Mavericks investment could pay off for the Adelsons, even without a gambling business in Texas.

"It's a very smart family, and sports assets have performed great," said Jason Ader, a former Las Vegas Sands board member who runs SpringOwl Asset Management. "NBA teams are marquis assets that are likely to continue to appreciate."

Cuban bought his stake in the Mavericks for $285 million in 2000. Forbes recently valued the team at $4.5 billion, the seventh-highest value in the NBA. The team won the NBA title in 2011. It currently features superstars Luka Doncic and Kyrie Irving.

CNBC has reached out to Cuban for comment. The NBA has not commented, and the Mavericks referred questions to the Adelsons.

–CNBC's Jessica Golden contributed to this article.