It is rare for a city to add professional sports teams at the rate at which Las Vegas is going:

With the potential for a city to add an NBA franchise in time for 2028, Vegas could go from no Big Four teams to become the 13th city with an MLB, NBA, NFL and NHL team in the span of 11 years.

Several things may have happened in a relatively short amount of time:

1. The city has grown rapidly in recent decades. The city had 125,787 people in 1970 (too small to have 4 sports franchises), 258,295 in 1990 (still on the smaller side), and 583,756 people in 2010 (a big city).
2. It is a new market. This presents a chance to have new fans.
3. Gambling is now okay with every major sport because of the revenue generated. That obstacle is gone.
4. The city and other governments are willing to provide public money for stadiums. Owners and teams really like this.

At some point, Las Vegas will not grow like it has in the past (it already slowed between 2010 to 2020 to 10%). At some point, a team might want to leave Las Vegas for greener pastures. But for now, Las Vegas is a shiny new sports city. If the NBA does indeed start a franchise there in the next few years, the teams in the four major sports help give the city and region a certain status.