New arena already has a sponsor (credit to 𝕏)
In all seriousness, these stadiums, if done right, can be a huge catalyst for growth around them, even when the surrounding development isn't planned from the outset. Petco Park in San Diego is a great example. Built on the outskirts of downtown San Diego in a not-so-pleasant area, it has completely transformed the area and is now one of the most iconic parts of the city, bustling with activity, new residents, new restaurants, etc. They got lucky though, the vote to help fund construction happened just a month after the Padres made the 1998 World Series. And the construction did jumpstart investment around it, this old
research article from Stanford University talks about the projects that came about after the stadium opened. "By 2007 (three years after the ballpark opened), redevelopment projects worth approximately $4.25 billion had been completed, were underway, or were planned. Of these, $4 billion was privately funded."